{"rowid": 242, "title": "Creating My First Chrome Extension", "contents": "Writing a Chrome Extension isn\u2019t as scary at it seems!\nNot too long ago, I used a Chrome extension called 20 Cubed. I\u2019m far-sighted, and being a software engineer makes it difficult to maintain distance vision. So I used 20 Cubed to remind myself to look away from my screen and rest my eyes. I loved its simple interface and design. I loved it so much, I often forgot to turn it off in the middle of presentations, where it would take over my entire screen. Oops.\nUnfortunately, the developer stopped updating the extension and removed it from Chrome\u2019s extension library. I was so sad. None of the other eye rest extensions out there matched my design aesthetic, so I decided to create my own! Want to do the same?\nFortunately, Google has some respectable documentation on how to create an extension. And remember, Chrome extensions are just HTML, CSS, and JavaScript. You can add libraries and frameworks, or you can just code the \u201cold-fashioned\u201d way. Sky\u2019s the limit!\nSetup\nBut first, some things you\u2019ll need to know about before getting started:\n\nCallbacks\nTimeouts\nChrome Dev Tools\n\nDeveloping with Chrome extension methods requires a lot of callbacks. If you\u2019ve never experienced the joy of callback hell, creating a Chrome extension will introduce you to this concept. However, things can get confusing pretty quickly. I\u2019d highly recommend brushing up on that subject before getting started.\nHyperbole and a Half\nTimeouts and Intervals are another thing you might want to brush up on. While creating this extension, I didn\u2019t consider the fact that I\u2019d be juggling three timers. And I probably would\u2019ve saved time organizing those and reading up on the Chrome extension Alarms documentation beforehand. But more on that in a bit.\nOn the note of organization, abstraction is important! You might have any combination of the following:\n\nThe Chrome extension options page\nThe popup from the Chrome Menu\nThe windows or tabs you create\nThe background scripts\n\nAnd that can get unwieldy. You might also edit the existing tabs or windows in the browser, which you\u2019ll probably want as a separate script too. Note that this tutorial only covers creating your own customized window rather than editing existing windows or tabs.\nAlright, now that you know all that up front, let\u2019s get going!\nDocumentation\nTL;DR READ THE DOCS.\nA few things to get started:\n\nRead Google\u2019s primer on browser extensions\nHave a look at their Getting started tutorial\nCheck out their overview on Chrome Extensions\n\nThis overview discusses the Chrome extension files, architecture, APIs, and communication between pages. Funnily enough, I only discovered the Overview page after creating my extension.\nThe manifest.json file gives the browser information about the extension, including general information, where to find your extension files and icons, and API permissions required. Here\u2019s what my manifest.json looked like, for example:\nhttps://github.com/jennz0r/eye-rest/blob/master/manifest.json\nBecause I\u2019m a visual learner, I found the images that describe the extension\u2019s architecture most helpful.\n\nTo clarify this diagram, the background.js file is the extension\u2019s event handler. It\u2019s constantly listening for browser events, which you\u2019ll feed to it using the Chrome Extension API. Google says that an effective background script is only loaded when it is needed and unloaded when it goes idle.\nThe Popup is the little window that appears when you click on an extension\u2019s icon in the Chrome Menu. It consists of markup and scripts, and you can tell the browser where to find it in the manifest.json under page_action: { \"default_popup\": FILE_NAME_HERE }.\nThe Options page is exactly as it says. This displays customizable options only visible to the user when they either right-click on the Chrome menu and choose \u201cOptions\u201d under an extension. This also consists of markup and scripts, and you can tell the browser where to find it in the manifest.json under options_page: FILE_NAME_HERE.\nContent scripts are any scripts that will interact with any web windows or tabs that the user has open. These scripts will also interact with any tabs or windows opened by your extension.\nDebugging\nA quick note: don\u2019t forget the debugging tutorial!\nJust like any other Chrome window, every piece of an extension has an inspector and dev tools. If (read: when) you run into errors (as I did), you\u2019re likely to have several inspector windows open \u2013 one for the background script, one for the popup, one for the options, and one for the window or tab the extension is interacting with.\nFor example, I kept seeing the error \u201cThis request exceeds the MAX_WRITE_OPERATIONS_PER_HOUR quota.\u201d Well, it turns out there are limitations on how often you can sync stored information.\nAnother error I kept seeing was \u201cAlarm delay is less than minimum of 1 minutes. In released .crx, alarm \u201cALARM_NAME_HERE\u201d will fire in approximately 1 minutes\u201d. Well, it turns out there are minimum interval times for alarms.\nChrome Extension creation definitely benefits from debugging skills. Especially with callbacks and listeners, good old fashioned console.log can really help!\nMe adding a ton of `console.log`s while trying to debug my alarms.\nEye Rest Functionality\nOk, so what is the extension I created? Again, it\u2019s a way to rest your eyes every twenty minutes for twenty seconds. So, the basic functionality should look like the following:\n\nIf the extension is running AND\nIf the user has not clicked Pause in the Popup HTML AND\nIf the counter in the Popup HTML is down to 00:00 THEN\n\nOpen a new window with Timer HTML AND\nStart a 20 sec countdown in Timer HTML AND\nReset the Popup HTML counter to 20:00\n\nIf the Timer HTML is down to 0 sec THEN\n\nClose that window. Rinse. Repeat.\n\n\nSounds simple enough, but wow, these timers became convoluted! Of all the Chrome extensions I decided to create, I decided to make one that\u2019s heavily dependent on time, intervals, and having those in sync with each other. In other words, I made this unnecessarily complicated and didn\u2019t realize until I started coding.\nFor visual reference of my confusion, check out the GitHub repository for Eye Rest. (And yes, it\u2019s a pun.)\nAPI\nNow let\u2019s discuss the APIs that I used to build this extension.\nAlarms\nWhat even are alarms? I didn\u2019t know either.\nAlarms are basically Chrome\u2019s setTimeout and setInterval. They exist because, as Google says\u2026\n\nDOM-based timers, such as window.setTimeout() or window.setInterval(), are not honored in non-persistent background scripts if they trigger when the event page is dormant.\n\nFor more information, check out this background migration doc.\nOne interesting note about alarms in Chrome extensions is that they are persistent. Garbage collection with Chrome extension alarms seems unreliable at best. I didn\u2019t have much luck using the clearAll method to remove alarms I created on previous extension loads or installs. A workaround (read: hack) is to specify a unique alarm name every time your extension is loaded and clearing any other alarms without that unique name.\nBackground Scripts\nFor Eye Rest, I have two background scripts. One is my actual initializer and event listener, and the other is a helpers file.\nI wanted to share a couple of functions between my Background and Popup scripts. Specifically, the clearAndCreateAlarm function. I wanted my background script to clear any existing alarms, create a new alarm, and add remaining time until the next alarm to local storage immediately upon extension load. To make the function available to the Background script, I added helpers.js as the first item under background > scripts in my manifest.json.\nI also wanted my Popup script to do the same things when the user has unpaused the extension\u2019s functionality. To make the function available to the Popup script, I just include the helpers script in the Popup HTML file.\nOther APIs\nWindows\nI use the Windows API to create the Timer window when the time of my alarm is up. The window creation is initiated by my Background script.\nOne day, while coding late into the evening, I found it very confusing that the window.create method included url as an option. I assumed it was meant to be an external web address. A friend pondered that there must be an option to specify the window\u2019s HTML. Until then, it hadn\u2019t dawned on me that the url could be relative. Duh. I was tired!\nI pass the timer.html as the url option, as well as type, size, position, and other visual options.\nStorage\nMaybe you want to pass information back and forth between the Background script and your Popup script? You can do that using Chrome or local storage. One benefit of using local storage over Chrome\u2019s storage is avoiding quotas and write operation maximums.\nI wanted to pass the time at which the latest alarm was set, the time to the next alarm, and whether or not the timer is paused between the Background and Popup scripts. Because the countdown should change every second, it\u2019s quite complicated and requires lots of writes. That\u2019s why I went with the user\u2019s local storage. You can see me getting and setting those variables in my Background, Helper, and Popup scripts. Just search for date, nextAlarmTime, and isPaused.\nDeclarative Content\nThe Declarative Content API allows you to show your extension\u2019s page action based on several type of matches, without needing to take a host permission or inject a content script. So you\u2019ll need this to get your extension to work in the browser!\nYou can see me set this in my Background script. Because I want my extension\u2019s popup to appear on every page one is browsing, I leave the page matchers empty.\nThere are many more APIs for Chrome apps and extensions, so make sure to surf around and see what features are available!\nThe Extension\nHere\u2019s what my original Popup looked like before I added styles.\nAnd here\u2019s what it looks like with new styles. I guess I\u2019m going for a Nickelodeon feel.\nAnd here\u2019s the Timer window and Popup together! \nPublishing\nPublishing is a cinch. You just zip up your files, create a new or use an existing Google Developer account, upload the files, add some details, and pay a one time $5 fee. That\u2019s all! Then your extension will be available on the Chrome extension store! Neato :D\nMy extension is now available for you to install.\nConclusion\nI thought creating a time based Chrome Extension would be quick and easy. I was wrong. It was more complicated than I thought! But it\u2019s definitely achievable with some time, persistence, and good ole Google searches.\nEventually, I\u2019d like to add more interactive elements to Eye Rest. For example, hitting the YouTube API to grab a silly or cute video as a reward for looking away during the 20 sec countdown and not closing the timer window. This harkens back to one of my first web projects, Toothtimer, from 2012. Or maybe a way to change the background colors of the Timer and Popup!\nEither way, with Eye Rest\u2019s framework built out, I\u2019m feeling fearless about future feature adds! Building this Chrome extension took some broken nails, achy shoulders, and tired eyes, but now Eye Rest can tell me to give my eyes a break every 20 minutes.", "year": "2018", "author": "Jennifer Wong", "author_slug": "jenniferwong", "published": "2018-12-05T00:00:00+00:00", "url": "https://24ways.org/2018/my-first-chrome-extension/", "topic": "code"}
{"rowid": 243, "title": "Researching a Property in the CSS Specifications", "contents": "I frequently joke that I\u2019m \u201creading the specs so you don\u2019t have to\u201d, as I unpack some detail of a CSS spec in a post on my blog, some documentation for MDN, or an article on Smashing Magazine. However waiting for someone like me to write an article about something is a pretty slow way to get the information you need. Sometimes people like me get things wrong, or specifications change after we write a tutorial. \nWhat if you could just look it up yourself? That\u2019s what you get when you learn to read the CSS specifications, and in this article my aim is to give you the basic details you need to grab quick information about any CSS property detailed in the CSS specs.\nWhere are the CSS Specifications?\nThe easiest way to see all of the CSS specs is to take a look at the Current Work page in the CSS section of the W3C Website. Here you can see all of the specifications listed, the level they are at and their status. There is also a link to the specification from this page. I explained CSS Levels in my article Why there is no CSS 4.\nWho are the specifications for?\nCSS specifications are for everyone who uses CSS. You might be a browser engineer - referred to as an implementor - needing to know how to implement a feature, or a web developer - referred to as an author - wanting to know how to use the feature. The fact that both parties are looking at the same document hopefully means that what the browser displays is what the web developer expected.\nWhich version of a spec should I look at?\nThere are a couple of places you might want to look. Each published spec will have the latest published version, which will have TR in the URL and can be accessed without a date (which is always the newest version) or at a date, which will be the date of that publication. If I\u2019m referring to a particular Working Draft in an article I\u2019ll typically link to the dated version. That way if the information changes it is possible for someone to see where I got the information from at the time of writing.\nIf you want the very latest additions and changes to the spec, then the Editor\u2019s Draft is the place to look. This is the version of the spec that the editors are committing changes to. If I make a change to the Multicol spec and push it to GitHub, within a few minutes that will be live in the Editor\u2019s Draft. So it is possible there are errors, bits of text that we are still working out and so on. The Editor\u2019s Draft however is definitely the place to look if you are wanting to raise an issue on a spec, as it may be that the issue you are about to raise is already fixed.\nIf you are especially keen on seeing updates to specifications keep an eye on https://drafts.csswg.org/ as this is a list of drafts, along with the date they were last updated.\nHow to approach a spec\nThe first thing to understand is that most CSS Specifications start with the most straightforward information, and get progressively further into the weeds. For an author the initial examples and explanations are likely to be of interest, and then the property definitions and examples. Therefore, if you are looking at a vast spec, know that you probably won\u2019t need to read all the way to the bottom, or read every section in detail.\nThe second thing that is useful to know about modern CSS specifications is how modularized they are. It really never is a case of finding everything you need in a single document. If we tried to do that, there would be a lot of repetition and likely inconsistency between specs. There are some key specifications that many other specifications draw on, such as:\n\nValues and Units\nIntrinsic and Extrinsic Sizing\nBox Alignment\n\nWhen something is defined in another specification the spec you are reading will link to it, so it is worth opening that other spec in a new tab in order that you can refer back to it as you explore.\nResearching your property\nAs an example we will take a look at the property grid-auto-rows, this property defines row tracks in the implicit grid when using CSS Grid Layout. The first thing you will need to do is find out which specification defines this property.\nYou might already know which spec the property is part of, and therefore you could go directly to the spec and search using your browser or look in the navigation for the spec to find it. Alternatively, you could take a look at the CSS Property Index, which is an automatically generated list of CSS Properties.\nClicking on a property will take you to the TR version of the spec, the latest published draft, and the definition of that property in it. This definition begins with a panel detailing the syntax of this property. For grid-auto-rows, you can see that it is listed along with grid-auto-columns as these two properties are essentially identical. They take the same values and work in the same way, one for rows and the other for columns.\nValue\nFor value we can see that the property accepts a value <track-size>. The next thing to do is to find out what that actually means, clicking  will take you to where it is defined in the Grid spec.\nThe <track-size> value is defined as accepting various values:\n\n<track-breadth>\nminmax( <inflexible-breadth> , <track-breadth> )\nfit-content( <length-percentage>\n\nWe need to head down the rabbit hole to find out what each of these mean. From here we essentially go down line by line until we have unpacked the value of track-size.\n<track-breadth> is defined just below <track-size> as:\n\n<length-percentage>\n<flex>\nmin-content\nmax-content\nauto\n\nSo these are all things that would be valid to use as a value for grid-auto-rows.\nThe first value of <length-percentage> is something you will see in many specifications as a value. It means that you can use a length unit - for example px or em - or a percentage. Some properties only accept a <length> in which case you know that you cannot use a percentage as the value. This means that you could have grid-auto-rows with any of the following values.\ngrid-auto-rows: 100px;\ngrid-auto-rows: 1em;\ngrid-auto-rows: 30%;\nWhen using percentages, it is important to know what it is a percentage of. As a percentage has to resolve from something. There is text in the spec which explains how column and row percentages work.\n\n\u201c<percentage> values are relative to the inline size of the grid container in column grid tracks, and the block size of the grid container in row grid tracks.\u201d\n\nThis means that in a horizontal writing mode such as when using English, a percentage when used as a track-size in grid-auto-columns would be a percentage of the width of the grid, and a percentage in grid-auto-rows a percentage of the height of the grid.\nThe second value of <flex> is also defined here, as \u201cA non-negative dimension with the unit fr specifying the track\u2019s flex factor.\u201d This is the fr unit, and the spec links to a fuller definition of fr as this unit is only used in Grid Layout so it is therefore defined in the grid spec. We now know that a valid value would be:\ngrid-auto-rows: 1fr;\nThere is some useful information about the fr unit in this part of the spec. It is noted that the fr unit has an automatic minimum. This means that 1fr is really minmax(auto, 1fr). This is why having a number of tracks all at 1fr does not mean that all are equal sized, as a larger item in any of the tracks would have a large auto size and therefore would be larger after spare space had been distributed.\nWe then have min-content and max-content. These keywords can be used for track sizing and the specification defines what they mean in the context of sizing a track, representing the min and max-sizing contributions of the grid tracks. You will see that there are various terms linked in the definition, so if you do not know what these mean you can follow them to find out.\nFor example the spec links max-content contribution to the CSS Intrinsic and Extrinsic Sizing specification. This is one of those specs which is drawn on by many other specifications. If we follow that link we can read the definition there and follow further links to understand what each term means. The more that you read specifications the more these terms will become familiar to you. Just like learning a foreign language, at first you feel like you have to look up every little thing. After a while you remember the vocabulary.\nWe can now add min-content and max-content to our available values.\ngrid-auto-rows: min-content;\ngrid-auto-rows: max-content;\nThe final item in our list is auto. If you are familiar with using Grid Layout, then you are probably aware that an auto sized track for will grow to fit the content used. There is an interesting note here in the spec detailing that auto sized rows will stretch to fill the grid container if there is extra space and align-content or justify-content have a value of stretch. As stretch is the default value, that means these tracks stretch by default. Tracks using other types of length will not behave like this.\ngrid-auto-rows: auto;\nSo, this was the list for <track-breadth>, the next possible value is minmax( <inflexible-breadth> , <track-breadth> ). So this is telling us that we can use minmax() as a value, the final (max) value will be <track-breadth> and we have already unpacked all of the allowable values there. The first value (min) is detailed as an <inflexible-breadth>. If we look at the values for this, we discover that they are the same as <track-breadth>, minus the <flex> value:\n\n<length-percentage>\nmin-content\nmax-content\nauto\n\nWe already know what all of these do, so we can add possible minmax() values to our list of values for <track-size>.\ngrid-auto-rows: minmax(100px, 200px);\ngrid-auto-rows: minmax(20%, 1fr);\ngrid-auto-rows: minmax(1em, auto);\ngrid-auto-rows: minmax(min-content, max-content);\nFinally we can use fit-content( <length-percentage>. We can see that fit-content takes a value of <length-percentage> which we already know to be either a length unit, or a percentage. The spec details how fit-content is worked out, and it essentially allows a track which acts as if you had used the max-content keyword, however the track stops growing when it hits the length passed to it.\ngrid-auto-rows: fit-content(200px);\ngrid-auto-rows: fit-content(20%);\nThose are all of our possible values, and to round things off, check again at the initial <track-size> value, you can see it has a little + sign next to it, click that and you will be taken to the CSS Values and Units module to find that, \u201cA plus (+) indicates that the preceding type, word, or group occurs one or more times.\u201d This means that we can pass a single track size to grid-auto-rows or multiple track sizes as a space separated list. Below the box is an explanation of what happens if you pass in more than one track size:\n\n\u201cIf multiple track sizes are given, the pattern is repeated as necessary to find the size of the implicit tracks. The first implicit grid track after the explicit grid receives the first specified size, and so on forwards; and the last implicit grid track before the explicit grid receives the last specified size, and so on backwards.\u201d\n\nTherefore with the following CSS, if five implicit rows were needed they would be as follows:\n\n100px\n1fr\nauto\n100px\n1fr\n\n.grid {\n    display: grid;\n    grid-auto-rows: 100px 1fr auto;\n}\nInitial\nWe can now move to the next line in the box, and you\u2019ll be glad to know that it isn\u2019t going to require as much unpacking! This simply defines the initial value for grid-auto-rows. If you do not specify anything, created rows will be auto sized. All CSS properties have an initial value that they will use if they are invoked as part of the usage of the specification they are in, but you do not set a value for them. In the case of grid-auto-rows it is used whenever rows are created in the implicit grid, so it needs to have a value to be used even if you do not set one.\nApplies to\nThis line tells us what this property is used for. Some properties are used in multiple places. For example if you look at the definition for justify-content in the Box Alignment specification you can see it is used in multicol containers, flex containers, and grid containers. In our case the property only applies for grid containers.\nInherited\nThis tells us if the property can be inherited from a parent element if it is not set. In the case of grid-auto-rows it is not inherited. A property such as color is inherited, so you do not need to set it on each element.\nPercentages\nAre percentages allowed for this property, and if so how are they calculated. In this case we are referred to the definition for grid-template-columns and grid-template-rows where we discover that the percentage is from the corresponding dimension of the content area.\nMedia\nThis defines the media group that the property belongs to. In this case visual.\nComputed Value\nThis details how the value is resolved. The grid-auto-rows property again refers to track sizing as defined for grid-template-columns and grid-template-rows, which tells us the computed value is as specified with lengths made absolute.\nCanonical Order\nIf you have a property\u2013generally a shorthand property\u2013which takes multiple values in a set order, then those values need to be serialized in the order detailed in the grammar for that property. In general you don\u2019t need to worry about this value in the table.\nAnimation Type\nThis details whether the property can be animated, and if so what type of animation. This is useful if you are trying to animate something and not getting the result that you expect. Note that just because something is listed in the spec as animatable does not mean that browsers will have implemented animation for that property yet!\nThat\u2019s (mostly) it!\nSometimes the property will have additional examples - there is one underneath the table for grid-auto-rows. These are worth looking at as they will highlight usage of the property that the spec editor has felt could use an example. There may also be some additional text explaining anythign specific to this property.\nIn selecting grid-auto-rows I chose a fairly complex property in terms of the work we needed to do to unpack the value. Many properties are far simpler than this. However ultimately, even when you come across a complex value, it really is just a case of stepping through the definitions until you come to the bottom of the rabbit hole.\nBeing able to work out what is valid for each property is incredibly useful. It means you don\u2019t waste time trying to use a value that doesn\u2019t work for that property. You also may find that there are values you weren\u2019t aware of, that solve problems for you.\nFurther reading\nSpecifications are not designed to be user manuals, and while they often contain examples, these are pretty terse as they need to be clear to demonstrate their particular point. The manual for the Web Platform is MDN Web Docs. Pairing reading a specification with the examples and information on an MDN property page such as the one for grid-auto-rows is a really great way to ensure that you have all the information and practical usage examples you might need.\nYou may also find useful:\n\nValue Definition Syntax on MDN.\nThe MDN Glossary defines many common terms.\nUnderstanding the CSS Property Value Syntax goes into more detail in terms of reading the syntax.\nHow to read W3C Specs - from 2001 but still relevant.\n\nI hope this article has gone some way to demystify CSS specifications for you. Even if the specifications are not your preferred first stop to learn about new CSS, being able to go directly to the source and avoid having your understanding filtered by someone else, can be very useful indeed.", "year": "2018", "author": "Rachel Andrew", "author_slug": "rachelandrew", "published": "2018-12-14T00:00:00+00:00", "url": "https://24ways.org/2018/researching-a-property-in-the-css-specifications/", "topic": "code"}
{"rowid": 244, "title": "It\u2019s Beginning to Look a Lot Like XSSmas", "contents": "I dread the office Secret Santa. I have a knack for choosing well-meaning but inappropriate presents, like a bottle of port for a teetotaller, a cheese-tasting experience for a vegan, or heaven forbid, Spurs socks for an Arsenal supporter. Ok, the last one was intentional.\nIt\u2019s the same with gifting code. Once, I made a pattern library for A List Apart which I open sourced, and a few weeks later, a glaring security vulnerability was found in it. My gift was so generous that it enabled unrestricted access to any file on any public-facing server that hosted it.\nWith platforms like GitHub and npm, giving the gift of code is so easy it\u2019s practically a no-brainer. This giant, open source yankee swap helps us do our jobs without starting from scratch with every project. But like any gift-giving, it\u2019s also risky.\nVulnerabilities and Open Source\nOpen source code is not inherently more or less vulnerable than closed-source code. What makes it higher risk is that the same piece of code gets reused in lots of places, meaning a hacker can use the same exploit mechanism on the same vulnerable code in different apps.\nGraph showing the number of open source vulnerabilities published per year, from the State of Open Source Security 2017\nIn the first 24 ways article this year, Katie referenced a few different types of vulnerability:\n\nCross-site Request Forgery (also known as CSRF)\nSQL Injection\nCross-site Scripting (also known as XSS)\n\nThere are many more types of vulnerability, and those that live under the same category share similarities. \nFor example, my favourite \u2013 is it weird to have a favourite vulnerability? \u2013 is Cross Site Scripting (XSS), which allows for the injection of scripts into web pages. This is a really common vulnerability often unwittingly added by developers. OWASP (the Open Web Application Security Project) wrote a great article about how to prevent opening the door to XSS attacks \u2013 share it generously with your colleagues.\nMost vulnerabilities like this are not added intentionally \u2013 they\u2019re doors left ajar due to the way something has been scripted, like the over-generous code in my pattern library. \nOthers, though, are added intentionally. A few months ago, a hacker, disguised as a helpful elf, offered to take over the maintenance of a popular npm package that had been unmaintained for a couple of years. The owner had moved onto other projects, and was keen to see it continue to be maintained by someone else, so transferred ownership. Fast-forward 3 months, it was discovered that the individual had quietly added a malicious package to the codebase, and the obfuscated code in it had been unwittingly installed onto thousands of apps. The code added was designed to harvest Bitcoin if it was run alongside another application. It was only spotted due to a developer\u2019s curiosity.\nAnother tactic to get developers to unwittingly install malicious packages into their codebase is \u201ctyposquatting\u201d \u2013 back in August last year, npm reported that a user had been publishing packages with very similar names to popular packages (for example, crossenv instead of cross-env). \nThis is a big wakeup call for open source maintainers. Techniques like this are likely to be used more as the maintenance of open source libraries becomes an increasing burden to their owners. After all, starting a new project often has a greater reward than maintaining an existing one, but remember, an open source library is for life, not just for Christmas.\nSanta\u2019s on his sleigh\nIf you use open source libraries, chances are that these libraries also use open source libraries. Your app may only have a handful of dependencies, but tucked in the back of that sleigh may be a whole extra sack of dependencies known as deep dependencies (ones that you didn\u2019t directly install, but are dependencies of that dependency), and these can contain vulnerabilities too.\nLet\u2019s look at the npm package santa as an example. santa has 8 direct dependencies listed on npm. That seems pretty manageable. But that\u2019s just the tip of the iceberg \u2013 have a look at the full dependency tree which contains 109 dependencies \u2013 more dependencies than there are Christmas puns in this article. Only one of these direct dependencies has a vulnerability (at the time of writing), but there are actually 13 other known vulnerabilities in santa, which have been introduced through its deeper dependencies.\nFixing vulnerabilities \u2013 the ultimate christmas gift\nIf you\u2019re a maintainer of open source libraries, taking good care of them is the ultimate gift you can give. Keep your dependencies up to date, use a security tool to monitor and alert you when new vulnerabilities are found in your code, and fix or patch them promptly. This will help keep the whole open source ecosystem healthy.\nWhen you find out about a new vulnerability, you have some options:\nFix the vulnerability via an upgrade\nYou can often fix a vulnerability by upgrading the library to the latest version. Make sure you\u2019re using software that monitors your dependencies for new security issues and lets you know when a fix is ready, otherwise you may be unwittingly using a vulnerable version.\nPatch the vulnerable code\nSometimes, a fix for a vulnerable library isn\u2019t possible. This is often the case when a library is no longer being maintained, or the version of the library being used might be so out of date that upgrading it would cause a breaking change. Patches are bits of code that will fix that particular issue, but won\u2019t change anything else.\nSwitch to a different library\nIf the library you\u2019re using has no fix or patch, you may be better of switching it out for another one, particularly if it looks like it\u2019s being unmaintained.\nResponsibly disclosing vulnerabilities\nKnowing how to responsibly disclose vulnerabilities is something I\u2019m ashamed to admit that I didn\u2019t know about before I joined a security company. But it\u2019s so important! On discovering a new vulnerability, a developer has a few options: \n\nA malicious developer will exploit that vulnerability for their own gain. \nA reckless (or inexperienced) developer will disclose that vulnerability to the world without following a responsible disclosure process. This opens the door to an unethical developer exploiting the vulnerability. At Snyk, we monitor social media for mentions of newly found vulnerabilities so we can add them to our database and share fixes before they get exploited.\nAn ethical and aware developer will follow what\u2019s known as a \u201cresponsible disclosure process\u201d. They will contact the maintainer of the code privately, allowing reasonable time for them to release a fix for the issue and to give others who use that vulnerable code a chance to fix it too.\n\nIt\u2019s important to understand this process if you\u2019re a maintainer or contributor of code. It can be daunting when a report comes in, but understanding and following the right steps will help reduce the risk to the people who use that code.\nSo what does responsible disclosure look like? I\u2019ll take Node.js\u2019s security disclosure policy as an example. They ask that all security issues that are found in Node.js are reported there. (There\u2019s a separate process for bug found in third-party npm packages). Once you\u2019ve reported a vulnerability, they promise to acknowledge it within 24 hours, and to give a more detailed response within 48 hours. If they find that the issue is indeed a security bug, they\u2019ll give you regular updates about the progress they\u2019re making towards fixing it. As part of this, they\u2019ll figure out which versions are affected, and prepare fixes for them. They\u2019ll assign the vulnerability a CVE (Common Vulnerabilities and Exposures) ID and decide on an embargo date for public disclosure. On the date of the embargo, they announce the vulnerability in their Node.js security mailing list and deploy fixes to nodejs.org.\nTim Kadlec published an in-depth article about responsible disclosures if you\u2019re interested in knowing more. It has some interesting horror stories of what happened when the disclosure process was not followed.\nEncourage responsible disclosure\nAdd a SECURITY.md file to your project so someone who wants to message you about a vulnerability can do so without having to hunt around for contact details. Last year, Snyk published a State of Open Source Security report that found 79.5% of maintainers do not have a public disclosure policy. Those that did were considerably more likely to get notified privately about a vulnerability \u2013 73% of maintainers who had one had been notified, vs 21% of maintainers who hadn\u2019t published one one.\nStats from the State of Open Source Security 2017\nBug bounties\nSome companies run bug bounties to encourage the responsible disclosure of vulnerabilities. By offering a reward for finding and safely disclosing a vulnerability, it also reduces the enticement of exploiting a vulnerability over reporting it and getting a quick cash reward. Hackerone is a community of ethical hackers who pentest apps that have signed up for the scheme and get paid when they find a new vulnerability. Wordpress is one such participant, and you can see the long list of vulnerabilities that have been disclosed as part of that program.\nIf you don\u2019t have such a bounty, be prepared to get the odd vulnerability extortion email. Scott Helme, who founded securityheaders.com and report-uri.com, wrote a post about some of the requests he gets for a report about a critical vulnerability in exchange for money. \n\nOn one hand, I want to be as responsible as possible and if my users are at risk then I need to know and patch this issue to protect them. On the other hand this is such irresponsible and unethical behaviour that interacting with this person seems out of the question.\n\nA gift worth giving\nIt\u2019s time to brush the dust off those old gifts that we shared and forgot about. Practice good hygiene and run them through your favourite security tool \u2013 I\u2019m just a little biased towards Snyk, but as Katie mentioned, there\u2019s also npm audit if you use Node.js, and most source code managers like GitHub and GitLab have basic vulnerability alert capabilities.\nStats from the State of Open Source Security 2017\nMost importantly, patch or upgrade away those vulnerabilities away, and if you want to share that Christmas spirit, open fixes for your favourite open source projects, too.", "year": "2018", "author": "Anna Debenham", "author_slug": "annadebenham", "published": "2018-12-17T00:00:00+00:00", "url": "https://24ways.org/2018/its-beginning-to-look-a-lot-like-xssmas/", "topic": "code"}
{"rowid": 246, "title": "Designing Your Site Like It\u2019s 1998", "contents": "It\u2019s 20 years to the day since my wife and I started Stuff & Nonsense, our little studio and my outlet for creative ideas on the web. To celebrate this anniversary\u2014and my fourteenth contribution to 24 ways\u2014 I\u2019d like to explain how I would\u2019ve developed a design for Planes, Trains and Automobiles, one of my favourite Christmas films.\nMy design for Planes, Trains and Automobiles is fixed at 800px wide.\nDeveloping a <frameset> framework\nI\u2019ll start by using frames to set up the framework for this new website. Frames are individual pages\u2014one for navigation, the other for my content\u2014pulled together to form a frameset. Space is limited on lower-resolution screens, so by using frames I can ensure my navigation always remains visible. I can include any number of frames inside a <frameset> element.\nI add two rows to my <frameset>; the first is for my navigation and is 50px tall, the second is for my content and will resize to fill any available space. As I don\u2019t want frame borders or any space between my frames, I set frameborder and framespacing attributes to 0:\n<frameset frameborder=\"0\" framespacing=\"0\" rows=\"50,*\">\n[\u2026]\n</frameset>\nNext I add the source of my two frame documents. I don\u2019t want people to be able to resize or scroll my navigation, so I add the noresize attribute to that frame:\n<frameset frameborder=\"0\" framespacing=\"0\" rows=\"50,*\">\n<frame noresize scrolling=\"no\" src=\"nav.html\">\n<frame src=\"content.html\">\n</frameset>\nI do want links from my navigation to open in the content frame, so I give each <frame> a name so I can specify where I want links to open:\n<frameset frameborder=\"0\" framespacing=\"0\" rows=\"50,*\">\n<frame name=\"navigation\" noresize scrolling=\"no\" src=\"nav.html\">\n<frame name=\"content\" src=\"content.html\">\n</frameset>\nThe framework for this website is simple as it contains only two horizontal rows. Should I need a more complex layout, I can nest as many framesets\u2014and as many individual documents\u2014as I need:\n<frameset rows=\"50,*\">\n <frame name=\"navigation\">\n <frameset cols=\"25%,*\">\n  <frame name=\"sidebar\">\n  <frame name=\"content\">\n </frameset>\n</frameset>\nLetterbox framesets were common way to deal with multiple screen sizes. In a letterbox, the central frameset had a fixed height and width, while the frames on the top, right, bottom, and left expanded to fill any remaining space.\nHandling older browsers\nSadly not every browser supports frames, so I should send a helpful message to people who use older browsers asking them to upgrade. Happily, I can do that using noframes content:\n<noframes>\n<body>\n<p>This page uses frames, but your browser doesn\u2019t support them. \n    Please upgrade your browser.</p>\n</body>\n</noframes>\nForcing someone back into a frame\nSometimes, someone may follow a link to a page from a portal or search engine, or they might attempt to open it in a new window or tab. If that page properly belongs inside a <frameset>, people could easily miss out on other parts of a design. This short script will prevent this happening and because it\u2019s vanilla Javascript, it doesn\u2019t require a library such as jQuery:\n<script type=\"text/javascript\">\nif (top == self) {\n  location = 'frameset.html';\n}\n</script>\n\nLaying out my page\nBefore starting my layout, I add a few basic background and colour styles. I must include these attributes in every page on my website:\n<body background=\"img/container.jpg\" bgcolor=\"#fef7fb\" \n    link=\"#245eab\" alink=\"#245eab\" vlink=\"#3c146e\" text=\"#000000\">\nI want absolute control over how people experience my design and don\u2019t want to allow it to stretch, so I first need a <table> which limits the width of my layout to 800px. The align attribute will keep this <table> in the centre of someone\u2019s screen:\n<table width=\"800\" align=\"center\">\n <tr>\n  <td>[\u2026]</td>\n </tr>\n</table>\nAlthough they were developed for displaying tabular information, the cells and rows which make up the <table> element make it ideal for the precise implementation of a design. I need several tables\u2014often nested inside each other\u2014to implement my design. These include tables for a banner and three rows of content:\n<table width=\"800\" align=\"center\">\n <table>[\u2026]</table>\n <table>\n  <table>\n   <table>[\u2026]</table>\n  </table>\n </table>\n <table>[\u2026]</table>\n <table>[\u2026]</table>\n</table>\nThe width of the first table\u2014used for my banner\u2014is fixed to match the logo it contains. As I don\u2019t need borders, padding, or spacing between these cells, I use attributes to remove them:\n<table border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"587\" align=\"center\">\n <tr>\n  <td><img src=\"logo.gif\" border=\"0\" width=\"587\" alt=\"Logo\"></td>\n </tr>\n</table>\nThe next table\u2014which contains the largest image, introduction, and a call-to-action\u2014is one of the most complex parts of my design, so I need to ensure its layout is pixel perfect. To do that I add an extra row at the top of this table and fill each of its cells with tiny transparent images:\n<tr>\n <td><img src=\"spacer.gif\" width=\"593\" height=\"1\"></td>\n <td><img src=\"spacer.gif\" width=\"207\" height=\"1\"></td>\n</tr>\nThe height and width of these \u201cshims\u201d or \u201cspacers\u201d is only 1px but they will stretch to any size without increasing their weight on the page. This makes them perfect for performant website development.\nFor the hero of this design, I splice up the large image into three separate files and apply each slice as a background to the table cells. I also match the height of those cells to the background images:\n<tr>\n <td background=\"slice-1.jpg\" height=\"473\">\u00a0</td>\n <td background=\"slice-2.jpg\" height=\"473\">[\u2026]</td>\n</tr>\n\n<tr>\n <td background=\"slice-3.jpg\" height=\"388\">\u00a0</td>\n</tr>\nI use tables and spacer images throughout the rest of this design to lay out the various types of content with perfect precision. For example, to add a single-pixel border around my two columns of content, I first apply a blue background to an outer table along with 1px of cellspacing, then simply nest an inner table\u2014this time with a white background\u2014inside it:\n<table border=\"0\" cellpadding=\"1\" cellspacing=\"0\">\n <tr>\n  <td>\n   <table bgcolor=\"#ffffff\" border=\"0\" cellpadding=\"0\" cellspacing=\"0\">\n[\u2026]\n   </table>\n  </td>\n </tr>\n</table>\nAdding details\nTables are fabulous tools for laying out a page, but they\u2019re also useful for implementing details on those pages. I can use a table to add a gradient background, rounded corners, and a shadow to the button which forms my \u201cBuy the DVD\u201d call-to-action. First, I splice my button graphic into three slices; two fixed-width rounded ends, plus a narrow gradient which stretches and makes this button responsive. Then, I add those images as backgrounds and use spacers to perfectly size my button:\n<table border=\"0\" cellpadding=\"0\" cellspacing=\"0\">\n <tr>\n  <td background=\"btn-1.jpg\" border=\"0\" height=\"48\" width=\"30\"><img src=\"spacer.gif\" width=\"30\" height=\"1\"></td>\n\n  <td background=\"btn-2.jpg\" border=\"0\" height=\"48\">\n   <center>\n    <a href=\"\" target=\"_blank\"><b>Buy the DVD</b></a>\n   </center>\n  </td>\n\n  <td background=\"btn-3.jpg\" border=\"0\" height=\"48\" width=\"30\"><img src=\"spacer.gif\" width=\"30\" height=\"1\"></td>\n </tr>\n</table>\nI use those same elements to add details to headlines and lists too. Adding a \u201cbullet\u201d to each item in a list needs only two additional table cells, a circular graphic, and a spacer:\n<table border=\"0\" cellpadding=\"0\" cellspacing=\"0\">\n <tr>\n  <td width=\"10\"><img src=\"li.gif\" border=\"0\" width=\"8\" height=\"8\">\u00a0</td>\n  <td><img src=\"spacer.gif\" width=\"10\" height=\"1\">\u00a0</td>\n  <td>Directed by John Hughes</td>\n </tr>\n</table>\nImplementing a typographic hierarchy\nSo far I\u2019ve explained how to use frames, tables, and spacers to develop a layout for my content, but what about styling that content? I use <font> elements to change the typeface from the browser\u2019s default to any font installed on someone\u2019s device:\n<font face=\"Arial\">Planes, Trains and Automobiles is a comedy film [\u2026]</font>\nTo adjust the size of those fonts, I use the size attribute and a value between the smallest (1) and the largest (7) where 3 is the browser\u2019s default. I use a size of 4 for this headline and 2 for the text which follows:\n<font face=\"Arial\" size=\"4\"><b>Steve Martin</b></font>\n\n<font face=\"Arial\" size=\"2\">An American actor, comedian, writer, producer, and musician.</font>\nWhen I need to change the typeface, perhaps from a sans-serif like Arial to a serif like Times New Roman, I must change the value of the face attribute on every element on all pages on my website.\nNB: I use as many <br> elements as needed to create space between headlines and paragraphs.\nView the final result (and especially the source.)\nMy modern day design for Planes, Trains and Automobiles.\nI can imagine many people reading this and thinking \u201cThis is terrible advice because we don\u2019t develop websites like this in 2018.\u201d That\u2019s true.\nWe have the ability to embed any number of web fonts into our products and websites and have far more control over type features, leading, ligatures, and sizes:\nfont-variant-caps: titling-caps;\nfont-variant-ligatures: common-ligatures;\nfont-variant-numeric: oldstyle-nums;\nGrid has simplified the implementation of even the most complex compound grid down to just a few lines of CSS:\nbody {\n  display: grid;\n  grid-template-columns: 3fr 1fr 2fr 2fr 1fr 3fr;\n  grid-template-rows: auto;\n  grid-column-gap: 2vw;\n  grid-row-gap: 1vh;\n}\nFlexbox has made it easy to develop flexible components such as navigation links:\nnav ul { display: flex; }\nnav li { flex: 1; }\nJust one line of CSS can create multiple columns of fluid type:\nmain { column-width: 12em; }\nCSS Shapes enable text to flow around irregular shapes including polygons:\n[src*=\"main-img\"] {\n  float: left;\n  shape-outside: polygon(\u2026);\n}\nToday, we wouldn\u2019t dream of using images and a table to add a gradient, rounded corners, and a shadow to a button or link, preferring instead:\n.btn {\n  background: linear-gradient(#8B1212, #DD3A3C);\n  border-radius: 1em;\n  box-shadow: 0 2px 4px 0 rgba(0,0,0,0.50), inset 0 -1px 1px 0 rgba(0,0,0,0.50);\n}\nCSS Custom Properties, feature and media queries, filters, pseudo-elements, and SVG; the list of advances in HTML, CSS, and other technologies goes on. So does our understanding of how best to use them by separating content, structure, presentation, and behaviour. As 2018 draws to a close, we\u2019re certain we know how to design and develop products and websites better than we did at the end of 1998.\nStrange as it might seem looking back, in 1998 we were also certain our techniques and technologies were the best for the job. That\u2019s why it\u2019s dangerous to believe with absolute certainty that the frameworks and tools we increasingly rely on today\u2014tools like Bootstrap, Bower, and Brunch, Grunt, Gulp, Node, Require, React, and Sass\u2014will be any more relevant in the future than <font> elements, frames, layout tables, and spacer images are today.\nI have no prediction for what the web will be like twenty years from now. However, I want to believe we\u2019ll build on what we\u2019ve learned during these past two decades about the importance of accessibility, flexibility, and usability, and that the mistakes we made while infatuated by technologies won\u2019t be repeated.\n\nHead over to my website if you\u2019d like to read about how I\u2019d implement my design for \u2018Planes, Trains and Automobiles\u2019 today.", "year": "2018", "author": "Andy Clarke", "author_slug": "andyclarke", "published": "2018-12-23T00:00:00+00:00", "url": "https://24ways.org/2018/designing-your-site-like-its-1998/", "topic": "code"}
{"rowid": 247, "title": "Managing Flow and Rhythm with CSS Custom Properties", "contents": "An important part of designing user interfaces is creating consistent vertical rhythm between elements. Creating consistent, predictable space doesn\u2019t just make your web pages and views look better, but it can also improve the scan-ability. \nBrowsers ship with default CSS and these styles often create consistent rhythm for flow elements out of the box. The problem is though that we often reset these styles with a reset. Elements such as <div> and <section> also have no default margin or padding associated with them. \nI\u2019ve tried all sorts of weird and wonderful techniques to find a balance between using inherited CSS while also levelling the playing field for component driven front-ends with very little success. This experimentation is how I landed on the flow utility, though and I\u2019m going to show you how it works. Let\u2019s dive in!\nThe Flow utility\nWith the ever-growing number of folks working with component libraries and design systems, we could benefit from a utility that creates space for us, only when it\u2019s appropriate to do so. The problem with my previous attempts at fixing this is that the spacing values were very rigid. \nThat\u2019s fine for 90% of contexts, but sometimes, it\u2019s handy to be able to tweak the values based on the exact context of your component. This is where CSS Custom Properties come in handy.\nThe code\n.flow {\n  --flow-space: 1em;\n}  \n\n.flow > * + * { \n  margin-top: var(--flow-space);\n}\nWhat this code does is enable you to add a class of flow to an element which will then add margin-top to sibling elements within that element. We use the lobotomised owl selector to select these siblings. This approach enables an almost anonymous and automatic system which is ideal for component library based front-ends where components probably don\u2019t have any idea what surrounds them. \nThe other important part of this utility is the usage of the --flow-space custom property. We define it in the .flow component and each element within it will be spaced by --flow-space, by default. The beauty about setting this as a custom property is that custom properties also participate in the cascade, so we can utilise specificity to change it if we need it. Pretty cool, right? Let\u2019s look at some examples.\nA basic example\nSee the Pen CSS Flow Utility: Basic implementation by Andy Bell (@hankchizljaw) on CodePen.\nhttps://codepen.io/hankchizljaw/pen/LXqerj\nWhat we\u2019ve got in this example is some basic HTML content that has a class of flow on the parent article element. Because there\u2019s a very heavy-handed reset added as a dependency, all of the content would have been squished together without the flow utility. \nBecause our --flow-space custom property is set to 1em, the space between elements is 1X the font size of the element in question. This means that a <h2> in this context has a calculated margin-top value of 28.8px, because it has an assigned font size of 1.8rem. If we were to globally change the --flow-space value to 1.1em for example, we\u2019d affect everything because margin values would be calculated as 1.1X the font size. \nThis example looks great because using font size as the basis of rhythm works really well. What if we wanted to to tweak certain elements within this article, though? \nSee the Pen CSS Flow Utility: Tweaked Basic implementation by Andy Bell (@hankchizljaw) on CodePen.\nhttps://codepen.io/hankchizljaw/pen/qQgxaY\nI like lots of whitespace with my article layouts, so the 1em space isn\u2019t going to cut it for all elements. I like to provide plenty of space between headed sections, so I increase the --flow-space in these instances:\nh2 {\n  --flow-space: 3rem;\n}\nNotice also how I also switch over to using rem units? I want to make sure that these overrides are always based on the root font size. This is a personal preference of mine and you can use whatever units you want. Just be aware that it\u2019s better for accessibility to use flexible units like em, rem and %, so that a user\u2019s font size preferences are honoured. \nA more advanced example\nAlthough the flow utility is super useful for a plethora of contexts, it really shines when working with a few unrelated components. Instead of having to write specific layout CSS just for your particular context, you can use flow and --flow-space to create predictable and contextual space.\nSee the Pen CSS Flow Utility: Unrelated components by Andy Bell (@hankchizljaw) on CodePen.\nhttps://codepen.io/hankchizljaw/pen/ZmPGyL\nIn this example, we\u2019ve got ourselves a little prototype layout that features a media element, followed by a grid of features. By using flow, it was really quick and easy to generate space between those two main elements. It was also easy to create space within the components. For example, I added it to the .media__content element, so that the article\u2019s content would space itself:\n<article class=\"media__content flow\">\n  ...\n</article>\nSomething to remember though: the custom properties cascade in the same way that other CSS values do, so you\u2019ve got to keep that in mind. We\u2019ve got a great example of that in this example where because we\u2019ve got the flow utility on our .features component, which has a --flow-space override: the child elements of .features will inherit that value, so we\u2019ve had to set another value on the .features__list element.\n\u201cBut what about old browsers?\u201d, I hear you cry\nWe\u2019re using CSS Custom Properties that at the time of writing, have about 88% support. One thing we can do to remedy the other 12% of browsers is to set a default, traditional margin-top value of 1em, so it calculates itself based on the element\u2019s font-size:\n.flow {\n  --flow-space: 1em;\n}\n\n.flow > * + * { \n  margin-top: 1em;\n  margin-top: var(--flow-space);\n}\nThanks to the cascading and declarative nature of CSS, we can set that default margin-top value and then immediately set it to use the custom property instead. Browsers that understand Custom Properties will automatically apply them\u2014those that don\u2019t will ignore them. Yay for the cascade and progressive enhancement! \nWrapping up\nThis tiny little utility can bring great power for when you want to consistently space elements, vertically. It also\u2014thanks to the power of the modern web\u2014allows us to create contextual overrides without creating modifier classes or shame CSS. \nIf you\u2019ve got other methods of doing this sort of work, please let me know on Twitter. I\u2019d love to see what you\u2019re working on!", "year": "2018", "author": "Andy Bell", "author_slug": "andybell", "published": "2018-12-07T00:00:00+00:00", "url": "https://24ways.org/2018/managing-flow-and-rhythm-with-css-custom-properties/", "topic": "code"}
{"rowid": 249, "title": "Fast Autocomplete Search for Your Website", "contents": "Every website deserves a great search engine - but building a search engine can be a lot of work, and hosting it can quickly get expensive.\nI\u2019m going to build a search engine for 24 ways that\u2019s fast enough to support autocomplete (a.k.a. typeahead) search queries and can be hosted for free. I\u2019ll be using wget, Python, SQLite, Jupyter, sqlite-utils and my open source Datasette tool to build the API backend, and a few dozen lines of modern vanilla JavaScript to build the interface.\n\nTry it out here, then read on to see how I built it.\nFirst step: crawling the data\nThe first step in building a search engine is to grab a copy of the data that you plan to make searchable.\nThere are plenty of potential ways to do this: you might be able to pull it directly from a database, or extract it using an API. If you don\u2019t have access to the raw data, you can imitate Google and write a crawler to extract the data that you need.\nI\u2019m going to do exactly that against 24 ways: I\u2019ll build a simple crawler using wget, a command-line tool that features a powerful \u201crecursive\u201d mode that\u2019s ideal for scraping websites.\nWe\u2019ll start at the https://24ways.org/archives/ page, which links to an archived index for every year that 24 ways has been running.\nThen we\u2019ll tell wget to recursively crawl the website, using the --recursive flag.\nWe don\u2019t want to fetch every single page on the site - we\u2019re only interested in the actual articles. Luckily, 24 ways has nicely designed URLs, so we can tell wget that we only care about pages that start with one of the years it has been running, using the -I argument like this: -I /2005,/2006,/2007,/2008,/2009,/2010,/2011,/2012,/2013,/2014,/2015,/2016,/2017\nWe want to be polite, so let\u2019s wait for 2 seconds between each request rather than hammering the site as fast as we can: --wait 2\nThe first time I ran this, I accidentally downloaded the comments pages as well. We don\u2019t want those, so let\u2019s exclude them from the crawl using -X \"/*/*/comments\".\nFinally, it\u2019s useful to be able to run the command multiple times without downloading pages that we have already fetched. We can use the --no-clobber option for this.\nTie all of those options together and we get this command:\nwget --recursive --wait 2 --no-clobber \n  -I /2005,/2006,/2007,/2008,/2009,/2010,/2011,/2012,/2013,/2014,/2015,/2016,/2017 \n  -X \"/*/*/comments\" \n  https://24ways.org/archives/ \nIf you leave this running for a few minutes, you\u2019ll end up with a folder structure something like this:\n$ find 24ways.org\n24ways.org\n24ways.org/2013\n24ways.org/2013/why-bother-with-accessibility\n24ways.org/2013/why-bother-with-accessibility/index.html\n24ways.org/2013/levelling-up\n24ways.org/2013/levelling-up/index.html\n24ways.org/2013/project-hubs\n24ways.org/2013/project-hubs/index.html\n24ways.org/2013/credits-and-recognition\n24ways.org/2013/credits-and-recognition/index.html\n...\nAs a quick sanity check, let\u2019s count the number of HTML pages we have retrieved:\n$ find 24ways.org | grep index.html | wc -l\n328\nThere\u2019s one last step! We got everything up to 2017, but we need to fetch the articles for 2018 (so far) as well. They aren\u2019t linked in the /archives/ yet so we need to point our crawler at the site\u2019s front page instead:\nwget --recursive --wait 2 --no-clobber \n  -I /2018 \n  -X \"/*/*/comments\" \n  https://24ways.org/\nThanks to --no-clobber, this is safe to run every day in December to pick up any new content.\nWe now have a folder on our computer containing an HTML file for every article that has ever been published on the site! Let\u2019s use them to build ourselves a search index.\nBuilding a search index using SQLite\nThere are many tools out there that can be used to build a search engine. You can use an open-source search server like Elasticsearch or Solr, a hosted option like Algolia or Amazon CloudSearch or you can tap into the built-in search features of relational databases like MySQL or PostgreSQL.\nI\u2019m going to use something that\u2019s less commonly used for web applications but makes for a powerful and extremely inexpensive alternative: SQLite.\nSQLite is the world\u2019s most widely deployed database, even though many people have never even heard of it. That\u2019s because it\u2019s designed to be used as an embedded database: it\u2019s commonly used by native mobile applications and even runs as part of the default set of apps on the Apple Watch!\nSQLite has one major limitation: unlike databases like MySQL and PostgreSQL, it isn\u2019t really designed to handle large numbers of concurrent writes. For this reason, most people avoid it for building web applications.\nThis doesn\u2019t matter nearly so much if you are building a search engine for infrequently updated content - say one for a site that only publishes new content on 24 days every year.\nIt turns out SQLite has very powerful full-text search functionality built into the core database - the FTS5 extension.\nI\u2019ve been doing a lot of work with SQLite recently, and as part of that, I\u2019ve been building a Python utility library to make building new SQLite databases as easy as possible, called sqlite-utils. It\u2019s designed to be used within a Jupyter notebook - an enormously productive way of interacting with Python code that\u2019s similar to the Observable notebooks Natalie described on 24 ways yesterday.\nIf you haven\u2019t used Jupyter before, here\u2019s the fastest way to get up and running with it - assuming you have Python 3 installed on your machine. We can use a Python virtual environment to ensure the software we are installing doesn\u2019t clash with any other installed packages:\n$ python3 -m venv ./jupyter-venv\n$ ./jupyter-venv/bin/pip install jupyter\n# ... lots of installer output\n# Now lets install some extra packages we will need later\n$ ./jupyter-venv/bin/pip install beautifulsoup4 sqlite-utils html5lib\n# And start the notebook web application\n$ ./jupyter-venv/bin/jupyter-notebook\n# This will open your browser to Jupyter at http://localhost:8888/\nYou should now be in the Jupyter web application. Click New -> Python 3 to start a new notebook.\nA neat thing about Jupyter notebooks is that if you publish them to GitHub (either in a regular repository or as a Gist), it will render them as HTML. This makes them a very powerful way to share annotated code. I\u2019ve published the notebook I used to build the search index on my GitHub account. \n\u200b\n\nHere\u2019s the Python code I used to scrape the relevant data from the downloaded HTML files. Check out the notebook for a line-by-line explanation of what\u2019s going on.\nfrom pathlib import Path\nfrom bs4 import BeautifulSoup as Soup\nbase = Path(\"/Users/simonw/Dropbox/Development/24ways-search\")\narticles = list(base.glob(\"*/*/*/*.html\"))\n# articles is now a list of paths that look like this:\n# PosixPath('...24ways-search/24ways.org/2013/why-bother-with-accessibility/index.html')\ndocs = []\nfor path in articles:\n    year = str(path.relative_to(base)).split(\"/\")[1]\n    url = 'https://' + str(path.relative_to(base).parent) + '/'\n    soup = Soup(path.open().read(), \"html5lib\")\n    author = soup.select_one(\".c-continue\")[\"title\"].split(\n        \"More information about\"\n    )[1].strip()\n    author_slug = soup.select_one(\".c-continue\")[\"href\"].split(\n        \"/authors/\"\n    )[1].split(\"/\")[0]\n    published = soup.select_one(\".c-meta time\")[\"datetime\"]\n    contents = soup.select_one(\".e-content\").text.strip()\n    title = soup.find(\"title\").text.split(\" \u25c6\")[0]\n    try:\n        topic = soup.select_one(\n            '.c-meta a[href^=\"/topics/\"]'\n        )[\"href\"].split(\"/topics/\")[1].split(\"/\")[0]\n    except TypeError:\n        topic = None\n    docs.append({\n        \"title\": title,\n        \"contents\": contents,\n        \"year\": year,\n        \"author\": author,\n        \"author_slug\": author_slug,\n        \"published\": published,\n        \"url\": url,\n        \"topic\": topic,\n    })\nAfter running this code, I have a list of Python dictionaries representing each of the documents that I want to add to the index. The list looks something like this:\n[\n  {\n    \"title\": \"Why Bother with Accessibility?\",\n    \"contents\": \"Web accessibility (known in other fields as inclus...\",\n    \"year\": \"2013\",\n    \"author\": \"Laura Kalbag\",\n    \"author_slug\": \"laurakalbag\",\n    \"published\": \"2013-12-10T00:00:00+00:00\",\n    \"url\": \"https://24ways.org/2013/why-bother-with-accessibility/\",\n    \"topic\": \"design\"\n  },\n  {\n    \"title\": \"Levelling Up\",\n    \"contents\": \"Hello, 24 ways. Iu2019m Ashley and I sell property ins...\",\n    \"year\": \"2013\",\n    \"author\": \"Ashley Baxter\",\n    \"author_slug\": \"ashleybaxter\",\n    \"published\": \"2013-12-06T00:00:00+00:00\",\n    \"url\": \"https://24ways.org/2013/levelling-up/\",\n    \"topic\": \"business\"\n  },\n  ...\nMy sqlite-utils library has the ability to take a list of objects like this and automatically create a SQLite database table with the right schema to store the data. Here\u2019s how to do that using this list of dictionaries.\nimport sqlite_utils\ndb = sqlite_utils.Database(\"/tmp/24ways.db\")\ndb[\"articles\"].insert_all(docs)\nThat\u2019s all there is to it! The library will create a new database and add a table to it called articles with the necessary columns, then insert all of the documents into that table.\n(I put the database in /tmp/ for the moment - you can move it to a more sensible location later on.)\nYou can inspect the table using the sqlite3 command-line utility (which comes with OS X) like this:\n$ sqlite3 /tmp/24ways.db\nsqlite> .headers on\nsqlite> .mode column\nsqlite> select title, author, year from articles;\ntitle                           author        year      \n------------------------------  ------------  ----------\nWhy Bother with Accessibility?  Laura Kalbag  2013      \nLevelling Up                    Ashley Baxte  2013      \nProject Hubs: A Home Base for   Brad Frost    2013      \nCredits and Recognition         Geri Coady    2013      \nManaging a Mind                 Christopher   2013      \nRun Ragged                      Mark Boulton  2013      \nGet Started With GitHub Pages   Anna Debenha  2013      \nCoding Towards Accessibility    Charlie Perr  2013      \n...\n<Ctrl+D to quit>\nThere\u2019s one last step to take in our notebook. We know we want to use SQLite\u2019s full-text search feature, and sqlite-utils has a simple convenience method for enabling it for a specified set of columns in a table. We want to be able to search by the title, author and contents fields, so we call the enable_fts() method like this:\ndb[\"articles\"].enable_fts([\"title\", \"author\", \"contents\"])\nIntroducing Datasette\nDatasette is the open-source tool I\u2019ve been building that makes it easy to both explore SQLite databases and publish them to the internet.\nWe\u2019ve been exploring our new SQLite database using the sqlite3 command-line tool. Wouldn\u2019t it be nice if we could use a more human-friendly interface for that?\nIf you don\u2019t want to install Datasette right now, you can visit https://search-24ways.herokuapp.com/ to try it out against the 24 ways search index data. I\u2019ll show you how to deploy Datasette to Heroku like this later in the article.\nIf you want to install Datasette locally, you can reuse the virtual environment we created to play with Jupyter:\n./jupyter-venv/bin/pip install datasette\nThis will install Datasette in the ./jupyter-venv/bin/ folder. You can also install it system-wide using regular pip install datasette.\nNow you can run Datasette against the 24ways.db file we created earlier like so:\n./jupyter-venv/bin/datasette /tmp/24ways.db\nThis will start a local webserver running. Visit http://localhost:8001/ to start interacting with the Datasette web application.\nIf you want to try out Datasette without creating your own 24ways.db file you can download the one I created directly from https://search-24ways.herokuapp.com/24ways-ae60295.db\nPublishing the database to the internet\nOne of the goals of the Datasette project is to make deploying data-backed APIs to the internet as easy as possible. Datasette has a built-in command for this, datasette publish. If you have an account with Heroku or Zeit Now, you can deploy a database to the internet with a single command. Here\u2019s how I deployed https://search-24ways.herokuapp.com/ (running on Heroku\u2019s free tier) using datasette publish:\n$ ./jupyter-venv/bin/datasette publish heroku /tmp/24ways.db --name search-24ways\n-----> Python app detected\n-----> Installing requirements with pip\n\n-----> Running post-compile hook\n-----> Discovering process types\n       Procfile declares types -> web\n\n-----> Compressing...\n       Done: 47.1M\n-----> Launching...\n       Released v8\n       https://search-24ways.herokuapp.com/ deployed to Heroku\nIf you try this out, you\u2019ll need to pick a different --name, since I\u2019ve already taken search-24ways.\nYou can run this command as many times as you like to deploy updated versions of the underlying database.\nSearching and faceting\nDatasette can detect tables with SQLite full-text search configured, and will add a search box directly to the page. Take a look at http://search-24ways.herokuapp.com/24ways-b607e21/articles to see this in action.\n\u200b\n\nSQLite search supports wildcards, so if you want autocomplete-style search where you don\u2019t need to enter full words to start getting results you can add a * to the end of your search term. Here\u2019s a search for access* which returns articles on accessibility:\nhttp://search-24ways.herokuapp.com/24ways-ae60295/articles?_search=acces%2A\nA neat feature of Datasette is the ability to calculate facets against your data. Here\u2019s a page showing search results for svg with facet counts calculated against both the year and the topic columns:\nhttp://search-24ways.herokuapp.com/24ways-ae60295/articles?_search=svg&_facet=year&_facet=topic\nEvery page visible via Datasette has a corresponding JSON API, which can be accessed using the JSON link on the page - or by adding a .json extension to the URL:\nhttp://search-24ways.herokuapp.com/24ways-ae60295/articles.json?_search=acces%2A\nBetter search using custom SQL\nThe search results we get back from ../articles?_search=svg are OK, but the order they are returned in is not ideal - they\u2019re actually being returned in the order they were inserted into the database! You can see why this is happening by clicking the View and edit SQL link on that search results page.\nThis exposes the underlying SQL query, which looks like this:\nselect rowid, * from articles where rowid in (\n  select rowid from articles_fts where articles_fts match :search\n) order by rowid limit 101\nWe can do better than this by constructing a custom SQL query. Here\u2019s the query we will use instead:\nselect\n  snippet(articles_fts, -1, 'b4de2a49c8', '8c94a2ed4b', '...', 100) as snippet,\n  articles_fts.rank, articles.title, articles.url, articles.author, articles.year\nfrom articles\n  join articles_fts on articles.rowid = articles_fts.rowid\nwhere articles_fts match :search || \"*\"\n  order by rank limit 10;\nYou can try this query out directly - since Datasette opens the underling SQLite database in read-only mode and enforces a one second time limit on queries, it\u2019s safe to allow users to provide arbitrary SQL select queries for Datasette to execute.\nThere\u2019s a lot going on here! Let\u2019s break the SQL down line-by-line:\nselect\n  snippet(articles_fts, -1, 'b4de2a49c8', '8c94a2ed4b', '...', 100) as snippet,\nWe\u2019re using snippet(), a built-in SQLite function, to generate a snippet highlighting the words that matched the query. We use two unique strings that I made up to mark the beginning and end of each match - you\u2019ll see why in the JavaScript later on.\n  articles_fts.rank, articles.title, articles.url, articles.author, articles.year\nThese are the other fields we need back - most of them are from the articles table but we retrieve the rank (representing the strength of the search match) from the magical articles_fts table.\nfrom articles\n  join articles_fts on articles.rowid = articles_fts.rowid\narticles is the table containing our data. articles_fts is a magic SQLite virtual table which implements full-text search - we need to join against it to be able to query it.\nwhere articles_fts match :search || \"*\"\n  order by rank limit 10;\n:search || \"*\" takes the ?search= argument from the page querystring and adds a * to the end of it, giving us the wildcard search that we want for autocomplete. We then match that against the articles_fts table using the match operator. Finally, we order by rank so that the best matching results are returned at the top - and limit to the first 10 results.\nHow do we turn this into an API? As before, the secret is to add the .json extension. Datasette actually supports multiple shapes of JSON - we\u2019re going to use ?_shape=array to get back a plain array of objects:\nJSON API call to search for articles matching SVG\nThe HTML version of that page shows the time taken to execute the SQL in the footer. Hitting refresh a few times, I get response times between 2 and 5ms - easily fast enough to power a responsive autocomplete feature.\nA simple JavaScript autocomplete search interface\nI considered building this using React or Svelte or another of the myriad of JavaScript framework options available today, but then I remembered that vanilla JavaScript in 2018 is a very productive environment all on its own.\nWe need a few small utility functions: first, a classic debounce function adapted from this one by David Walsh:\nfunction debounce(func, wait, immediate) {\n  let timeout;\n  return function() {\n    let context = this, args = arguments;\n    let later = () => {\n      timeout = null;\n      if (!immediate) func.apply(context, args);\n    };\n    let callNow = immediate && !timeout;\n    clearTimeout(timeout);\n    timeout = setTimeout(later, wait);\n    if (callNow) func.apply(context, args);\n  };\n};\nWe\u2019ll use this to only send fetch() requests a maximum of once every 100ms while the user is typing.\nSince we\u2019re rendering data that might include HTML tags (24 ways is a site about web development after all), we need an HTML escaping function. I\u2019m amazed that browsers still don\u2019t bundle a default one of these:\nconst htmlEscape = (s) => s.replace(\n  />/g, '&gt;'\n).replace(\n  /</g, '&lt;'\n).replace(\n  /&/g, '&'\n).replace(\n  /\"/g, '&quot;'\n).replace(\n  /'/g, '&#039;'\n);\nWe need some HTML for the search form, and a div in which to render the results:\n<h1>Autocomplete search</h1>\n<form>\n  <p><input id=\"searchbox\" type=\"search\" placeholder=\"Search 24ways\" style=\"width: 60%\"></p>\n</form>\n<div id=\"results\"></div>\nAnd now the autocomplete implementation itself, as a glorious, messy stream-of-consciousness of JavaScript:\n// Embed the SQL query in a multi-line backtick string:\nconst sql = `select\n  snippet(articles_fts, -1, 'b4de2a49c8', '8c94a2ed4b', '...', 100) as snippet,\n  articles_fts.rank, articles.title, articles.url, articles.author, articles.year\nfrom articles\n  join articles_fts on articles.rowid = articles_fts.rowid\nwhere articles_fts match :search || \"*\"\n  order by rank limit 10`;\n\n// Grab a reference to the <input type=\"search\">\nconst searchbox = document.getElementById(\"searchbox\");\n\n// Used to avoid race-conditions:\nlet requestInFlight = null;\n\nsearchbox.onkeyup = debounce(() => {\n  const q = searchbox.value;\n  // Construct the API URL, using encodeURIComponent() for the parameters\n  const url = (\n    \"https://search-24ways.herokuapp.com/24ways-866073b.json?sql=\" +\n    encodeURIComponent(sql) +\n    `&search=${encodeURIComponent(q)}&_shape=array`\n  );\n  // Unique object used just for race-condition comparison\n  let currentRequest = {};\n  requestInFlight = currentRequest;\n  fetch(url).then(r => r.json()).then(d => {\n    if (requestInFlight !== currentRequest) {\n      // Avoid race conditions where a slow request returns\n      // after a faster one.\n      return;\n    }\n    let results = d.map(r => `\n      <div class=\"result\">\n        <h3><a href=\"${r.url}\">${htmlEscape(r.title)}</a></h3>\n        <p><small>${htmlEscape(r.author)} - ${r.year}</small></p>\n        <p>${highlight(r.snippet)}</p>\n      </div>\n    `).join(\"\");\n    document.getElementById(\"results\").innerHTML = results;\n  });\n}, 100); // debounce every 100ms\nThere\u2019s just one more utility function, used to help construct the HTML results:\nconst highlight = (s) => htmlEscape(s).replace(\n  /b4de2a49c8/g, '<b>'\n).replace(\n  /8c94a2ed4b/g, '</b>'\n);\nThis is what those unique strings passed to the snippet() function were for.\nAvoiding race conditions in autocomplete\nOne trick in this code that you may not have seen before is the way race-conditions are handled. Any time you build an autocomplete feature, you have to consider the following case:\n\nUser types acces\nBrowser sends request A - querying documents matching acces*\nUser continues to type accessibility\nBrowser sends request B - querying documents matching accessibility*\nRequest B returns. It was fast, because there are fewer documents matching the full term\nThe results interface updates with the documents from request B, matching accessibility*\nRequest A returns results (this was the slower of the two requests)\nThe results interface updates with the documents from request A - results matching access*\n\nThis is a terrible user experience: the user saw their desired results for a brief second, and then had them snatched away and replaced with those results from earlier on.\nThankfully there\u2019s an easy way to avoid this. I set up a variable in the outer scope called requestInFlight, initially set to null.\nAny time I start a new fetch() request, I create a new currentRequest = {} object and assign it to the outer requestInFlight as well.\nWhen the fetch() completes, I use requestInFlight !== currentRequest to sanity check that the currentRequest object is strictly identical to the one that was in flight. If a new request has been triggered since we started the current request we can detect that and avoid updating the results.\nIt\u2019s not a lot of code, really\nAnd that\u2019s the whole thing! The code is pretty ugly, but when the entire implementation clocks in at fewer than 70 lines of JavaScript, I honestly don\u2019t think it matters. You\u2019re welcome to refactor it as much you like.\nHow good is this search implementation? I\u2019ve been building search engines for a long time using a wide variety of technologies and I\u2019m happy to report that using SQLite in this way is genuinely a really solid option. It scales happily up to hundreds of MBs (or even GBs) of data, and the fact that it\u2019s based on SQL makes it easy and flexible to work with.\nA surprisingly large number of desktop and mobile applications you use every day implement their search feature on top of SQLite.\nMore importantly though, I hope that this demonstrates that using Datasette for an API means you can build relatively sophisticated API-backed applications with very little backend programming effort. If you\u2019re working with a small-to-medium amount of data that changes infrequently, you may not need a more expensive database. Datasette-powered applications easily fit within the free tier of both Heroku and Zeit Now.\nFor more of my writing on Datasette, check out the datasette tag on my blog. And if you do build something fun with it, please let me know on Twitter.", "year": "2018", "author": "Simon Willison", "author_slug": "simonwillison", "published": "2018-12-19T00:00:00+00:00", "url": "https://24ways.org/2018/fast-autocomplete-search-for-your-website/", "topic": "code"}
{"rowid": 253, "title": "Clip Paths Know No Bounds", "contents": "CSS Shapes are getting a lot of attention as browser support has increased for properties like shape-outside and clip-path. There are a few ways that we can use CSS Shapes, in particular with the clip-path property, that are not necessarily evident at first glance.\nThe basics of a clip path\nBefore we dig into specific techniques to expand on clip paths, we should first take a look at a basic shape and clip-path. Clip paths can apply a CSS Shape such as a circle(), ellipse(), inset(), or the flexible polygon() to any element. Everywhere in the element that is not within the bounds of our shape will be visually removed.\nUsing the polygon shape function, for example, we can create triangles, stars, or other straight-edged shapes as on Bennett Feely\u2019s Clippy. While fixed units like pixels can be used when defining vertices/points (where the sides meet), percentages will give more flexibility to adapt to the element\u2019s dimensions.\nSee the Pen Clip Path Box by Dan Wilson (@danwilson) on CodePen.\n\nSo for an octagon, we can set eight x, y pairs of percentages to define those points. In this case we start 30% into the width of the box for the first x and at the top of the box for the y and go clockwise. The visible area becomes the interior of the shape made by connecting these points with straight lines.\nclip-path: polygon(\n  30% 0%,\n  70% 0%,\n  100% 30%,\n  100% 70%,\n  70% 100%,\n  30% 100%,\n  0% 70%,\n  0% 30%\n);\nA shape with less vertices than the eye can see\nIt\u2019s reasonable to look at the polygon() function and assume that we need to have one pair of x, y coordinates for every point in our shape. However, we gain some flexibility by thinking outside the box \u2014 or more specifically when we think outside the range of 0% - 100%.\nOur element\u2019s box model will be the ultimate boundary for a clip-path, but we can still define points that exist beyond that natural box for an element.\nSee the Pen CSS Shapes Know No Bounds by Dan Wilson (@danwilson) on CodePen.\n\nBy going beyond the 0% - 100% range we can turn a polygon with three points into a quadrilateral, a pentagon, or a hexagon. In this example the shapes used are all similar triangles defining three points, but due to exceeding the bounds for our element box we visually see one triangle and two pentagons.\nOur earlier octagon can similarly be made with only four points.\nSee the Pen Octagon with four points by Dan Wilson (@danwilson) on CodePen.\n\nMultiple shapes, one clip path\nWe can lean on this power of going beyond the bounds of our element to also create more than one visual shape with a single polygon().\nSee the Pen Multiple shapes from one clip-path by Dan Wilson (@danwilson) on CodePen.\n\nDepending on how we lay it out we can make each shape directly, but since we know we can move around in the space beyond the element\u2019s box, we can draw extra lines to help us get where we need to go next as needed.\nIt can also help us in slicing an element. Combined with CSS Variables, we can work with overlapping elements and clip each one into alternating strips. This example is two elements, each divided into a few rectangles.\nSee the Pen 24w: Sliced Icon by Dan Wilson (@danwilson) on CodePen.\n\nDifferent shapes with fill rules\nA polygon() is not just a collection of points. There is one more key piece to its puzzle according to the specification \u2014 the Fill Rule. The default value we have been using so far is nonzero, and the second option is evenodd. These two values help determine what is considered inside and outside the shape.\nSee the Pen A Star Multiways by Dan Wilson (@danwilson) on CodePen.\n\nAs lines intersect we can get into situations where pieces seemingly on the inside can be considered outside the shape boundary. When using the evenodd fill rule, we can determine if a given point is inside or outside the boundary by drawing a ray from the point in any direction. If the ray crosses an even number of the clip path\u2019s lines, the point is considered outside, and if it crosses an odd number the point is inside.\nOrder of operations\nIt is important to note that there are many CSS properties that affect the final composited appearance of an element via CSS Filters, Blend Modes, and more.\nThese compositing effects are applied in the order:\n\nCSS Filters (e.g. filter: blur(2px))\nClipping (e.g. what this article is about)\nMasking (Clipping\u2019s cousin)\nBlend Modes (e.g. mix-blend-mode: multiply)\nOpacity\n\nThis means if we want to have a star shape and blur it, the blur will happen before the clip. And since blurs are most noticeable around the edge of an element box, the effect might be completely lost since we have clipped away the element\u2019s box edges.\nSee the Pen Order of Filter + Clip by Dan Wilson (@danwilson) on CodePen.\n\nIf we want the edges of the star to be blurred, we do have the option to wrap our clipped element in a blurred parent element. The inner element will be rendered first (with its star clip) and then the parent will blur its contents normally.\nRevealing content with animation\nCSS Shapes can be transitioned and animated, allowing us to animate the visual area of our element without affecting the content within. For example, we can start with visually hidden content (fully clipped) and grow the clip path to reveal the content within. The important caveat for polygon() is that the number of points need to be the same for each keyframe, as well as the fill rule. Otherwise the browser will not have enough information to interpolate the intermediate values. \nSee the Pen Clip Path Shape Reveal by Dan Wilson (@danwilson) on CodePen.\n\nDon\u2019t keep CSS Shapes in a box\nClip paths give us some interesting new possibilities, especially when we think of them as more than just basic shapes. We may be heavily modifying the visual representation of our elements with clip-path, but the underlying content remains unchanged and accessible which makes this property fairly powerful.", "year": "2018", "author": "Dan Wilson", "author_slug": "danwilson", "published": "2018-12-20T00:00:00+00:00", "url": "https://24ways.org/2018/clip-paths-know-no-bounds/", "topic": "code"}
{"rowid": 255, "title": "Inclusive Considerations When Restyling Form Controls", "contents": "I would like to begin by saying 2018 was the year that we, as developers, visual designers, browser implementers, and inclusive design and experience specialists rallied together and achieved a long-sought goal: We now have the ability to fully style form controls, across all modern browsers, while retaining their ease of declaration, native functionality and accessibility.\nI would like to begin by saying all these things. However, they\u2019re not true. I think we spent the year debating about what file extension CSS should be written in, or something. Or was that last year? Maybe I\u2019m thinking of next year.\nReturning to reality, styling form controls is more tricky and time consuming these days rather than flat out \u201chard\u201d. In fact, depending on the length of the styling-leash a particular browser provides, there are controls you can style quite a bit. As for browsers with shorter leashes, there are other options to force their controls closer to the visual design you\u2019re tasked to match.\nHowever, when striving for custom styled controls, one must be careful not to forget about the inherent functionality and accessibility that many provide. People expect and deserve the products and services they use and pay for to work for them. If these services are visually pleasing, but only function for those who fit the handful of personas they\u2019ve been designed for, then we\u2019ve potentially deprived many people the experiences they deserve.\nQuick level setting\nGetting down to brass tacks, when creating custom styled form controls that should retain their expected semantics and functionality, we have to consider the following:\n\nMany form elements can be styled directly through standard and browser specific selectors, as well as through some clever styling of markup patterns. We should leverage these native options before reinventing any wheels.\nIt is important to preserve the underlying semantics of interactive controls. We must not unintentionally exclude people who use assistive technologies (ATs) that rely on these semantics. \nMake sure you test what you create. There is a lot of underlying complexity to form controls which may not be immediately apparent if they\u2019re judged solely by their visual presentation in a single browser, or with limited AT testing.\n\nVisually resetting and restyling form controls\nOver the course of 2018, I worked on a project where I tested and reported on the accessibility impact of styling various form controls. In conducting my research, I reviewed many of the form controls available in HTML, testing to see how malleable they were to direct styling from standardized CSS selectors. \nAs I expected, controls such as the various text fields could be restyled rather easily. However, other controls like radio buttons and checkboxes, or sub-elements of special text fields like date, search, and number spinners were resistant to standard-based styling. These particular controls and their sub-elements required specific pseudo-elements to reset and allow for restyling of some of their default presentation.\nSee the Pen form control styling comparisons by Scott (@scottohara) on CodePen.\nhttps://codepen.io/scottohara/pen/gZOrZm/\nOver the years, the ability to directly style form controls has been something many people have clamored for. However, one should realize the benefits of being able to restyle some of these controls may involve more effort than originally anticipated. \nIf you want to restyle a control from the ground up, then you must also recreate any :active, :focus, and :hover states for the control\u2014all those things that were previously taken care of by browsers. Not only that, but anything you restyle should also work with Windows High Contrast mode, styling for dark mode, and other OS-level settings that browser respect without you even realizing.   \n\n            You ever try playing with the accessibility settings of your display on macOS, or similar Windows setting?\n    \nIt is also worth mentioning that any browser prefixed pseudo-elements are not standardized CSS selectors. As MDN mentions at the top of their pages documenting these pseudo-elements:\n\nNon-standard\nThis feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.\n\nWhile this may be a deterrent for some, it\u2019s my opinion the risks are often only skin-deep. By which I mean if a non-standard selector does change, the control may look a bit quirky, but likely won\u2019t cease to function. A bug report which requires a CSS selector change can be an easy JIRA ticket to close, after all.\nCan\u2019t make it? Fake it.\nInternet Explorer 11 (IE11) is still neck-and-neck with other browsers in vying for the number 2 spot in desktop browser share. Due to IE not recognizing vendor-prefixed appearance properties, some essential controls like checkboxes won\u2019t render as intended. \nAdditionally, some controls like select boxes, file uploads, and sub-elements of date fields (calendar popups) cannot be modified by just relying on styling their HTML selectors alone. This means that unless your company designs and develops with a progressive enhancement, or graceful degradation mindset, you\u2019ll need to take a different approach in styling.\nGetting clever with markup and CSS\nThe following CodePen demonstrates how we can create a custom checkbox markup pattern. By mindfully utilizing CSS sibling selectors and positioning of the native control, we can create custom visual styling while also retaining the functionality and accessibility expectations of a native checkbox.\nSee the Pen Accessible Styled Native Checkbox by Scott (@scottohara) on CodePen.\nhttps://codepen.io/scottohara/pen/RqEayN/\nCustomizing checkboxes by visually hiding the input and styling well-placed markup with sibling selectors may seem old hat to some. However, many variations of these patterns do not take into account how their method of visually hiding the checkboxes can create discovery issues for certain screen reader navigation methods. For instance, if someone is using a mobile device and exploring by touch, how will they be able to drag their finger over an input that has been reduced to a single pixel, or positioned off screen?\nAs we move away from the simplicity of declaring a single HTML element and using clever CSS and markup patterns to create restyled form controls, we increase the need for additional testing to ensure no expected behaviors are lost. In other words, what should work in theory may not work in practice when you introduce the various different ways people may engage with a form control. It\u2019s worth remembering: what might be typical interactions for ourselves may be problematic if not impossible for others.\nLimitations to cleverness\nCreative coding will allow us to apply more consistent custom styles to some of the more problematic form controls. There will be a varied amount of custom markup, CSS, and sometimes JavaScript that will be needed to preserve the control\u2019s inherent usability and accessibility for each control we take this approach to.\nHowever, this method of restyling still doesn\u2019t solve for the lack of feature parity across different browsers. Nor is it a means to account for controls which don\u2019t have a native HTML element equivalent, such as a switch or multi-thumb range slider? Maybe there\u2019s a control that calls for a visual design or proposed user experience that would require too much fighting with a native control\u2019s behavior to be worth the level of effort to implement. Here\u2019s where we need to take another approach.\nUsing ARIA when appropriate\nSometimes we have no other option than to roll up our sleeves and start building custom form controls from scratch. Fair warning though: just because we\u2019re not leveraging a native HTML control as our foundation, it doesn\u2019t mean we have carte blanche to throw semantics out the window. Enter Accessible Rich Internet Applications (ARIA).\nARIA is a set of attributes that can modify existing elements, or extend HTML to include roles, properties and states that aren\u2019t native to the language. While divs and spans have no meaningful semantic information for us to leverage, with help from the ARIA specification and ARIA Authoring Practices we can incorporate these elements to help create the UI that we need while still following the first rule of Using ARIA:\n\nIf you can use a native HTML element or attribute with the semantics and behavior you require already built in, instead of re-purposing an element and adding an ARIA role, state or property to make it accessible, then do so.\n\nBy using these documents as guidelines, and testing our custom controls with people of various abilities, we can do our best to make sure a custom control performs as expected for as many people as possible.\nExceptions to the rule\nOne example of a control that allows for an exception to the first rule of Using ARIA would be a switch control.\nSwitches and checkboxes are similar components, in that they have both on/checked and off/unchecked states. However, checkboxes are often expected within the context of forms, or used to filter search queries on e-commerce sites. Switches are typically used to instantly enable or deactivate a particular setting at a component or app-based level, as this is their behavior in the native mobile apps in which they were popularized.\nWhile a switch control could be created by visually restyling a checkbox, this does not automatically mean that the underlying semantics and functionality will match the visual representation of the control. For example, the following CodePen restyles checkboxes to look like a switch control, but the semantics of the checkboxes remain which communicate a different way of interacting with the control than what you might expect from a native switch control.\nSee the Pen Switch Boxes - custom styled checkboxes posing as switches by Scott (@scottohara) on CodePen.\nhttps://codepen.io/scottohara/pen/XyvoeE/\nBy adding a role=\"switch\" to these checkboxes, we can repurpose the inherent checked/unchecked states of the native control, it\u2019s inherent ability to be focused by Tab key, and Space key to toggle state.\nBut while this is a valid approach to take in building a switch, how does this actually match up to reality?\nDoes it pass the test(s)?\nWhether deconstructing form controls to fully restyle them, or leveraging them and other HTML elements as a base to expand on, or create, a non-native form control, building it is just the start. We must test that what we\u2019ve restyled or rebuilt works the way people expect it to, if not better.\nWhat we must do here is run a gamut of comparative tests to document the functionality and usability of native form controls.  For example:\n\n\nIs the control implemented in all supported browsers?\nIf not: where are the gaps? Will it be necessary to implement a custom solution for the situations that degrade to a standard text field?  \nIf so: is each browser\u2019s implementation a good user experience? Is there room for improvement that can be tested against the native baseline?  \n\n\nTest with multiple input devices.\nWhere the control is implemented, what is the quality of the user experience when using different input devices, such as mouse, touchscreen, keyboard, speech recognition or switch device, to name a few.  \nYou\u2019ll find some HTML5 controls (like date pickers and number spinners) have additional UI elements that may not be announced to AT, or even allow keyboard accessibility. Often these controls can be adjusted by other means, such as text entry, or using arrow keys to increase or decrease values.  If restyling or recreating a custom version of a control like these, it  may make sense to maintain these native experiences as well.\n\n\nHow well does the control take to custom styles?\nIf a control can be styled enough to not need to be rebuilt from scratch, that\u2019s great! But make sure that there are no adverse affects on the accessibility of it.  For instance, range sliders can be restyled and maintain their functionality and accessibility.  However, elements like progress bars can be negatively affected by direct styling.  \nAlways test with different browser and AT pairings to ensure nothing is lost when controls are restyled.  \n\n\nDo specifications match reality?\nIf recreating controls to get around native limitations, such as the inability to style the options of a select element, or requiring a Switch control which is not native to HTML, do your solutions match user expectations?  \nFor instance, selects have unique picker interfaces on touch devices.  And switches have varied levels of support for different browser and screen reader pairings.  Test with real people, and check your analytics.  If these experiences don\u2019t match people\u2019s expectations, then maybe another solution is in order?  \n\n\nWrapping up\nWhile styling form controls is definitely easier than it\u2019s ever been, that doesn\u2019t mean that it\u2019s at all simple, nor will it likely ever be. The level of difficulty you\u2019re going to face is going to depend entirely on what it is you\u2019re hoping to style, add-on to, or recreate. And even if you build your custom control exactly to specification, you\u2019ll still be reliant on browsers and assistive technologies being able to fully understand the component they\u2019ve been presented.\nForms and their controls are an incredibly important part of what we need the Internet for. Paying bills, scheduling appointments, ordering groceries, renewing your license or even ordering gifts for the holidays. These are all important tasks that people should be able to complete with as little effort as possible. Especially since for some, completing these tasks online might be their only option.\n2018 didn\u2019t end up being the year we got full customization of form controls sorted out. But that\u2019s OK. If we can continue to mindfully work with what we have, and instead challenge ourselves to follow inclusive design principles, well thought out Form Design Patterns, and solve problems with an accessibility first approach, we may come to realize that we can get along just fine without fully branded drop downs.  \nAnd hey. There\u2019s always next year, right?", "year": "2018", "author": "Scott O'Hara", "author_slug": "scottohara", "published": "2018-12-13T00:00:00+00:00", "url": "https://24ways.org/2018/inclusive-considerations-when-restyling-form-controls/", "topic": "code"}
{"rowid": 256, "title": "Develop Your Naturalist Superpowers with Observable Notebooks and iNaturalist", "contents": "We\u2019re going to level up your knowledge of what animals you might see in an area at a particular time of year - a skill every naturalist* strives for -  using technology! Using iNaturalist and Observable Notebooks we\u2019re going to prototype seasonality graphs for particular species in an area, and automatically create a guide to what animals you might see in each month.\n*(a Naturalist is someone who likes learning about nature, not someone who\u2019s a fan of being naked, that\u2019s a \u2018Naturist\u2019\u2026 different thing!)\nLooking for critters in rocky intertidal habitats\nOne of my favourite things to do is going rockpooling, or as we call it over here in California, \u2018tidepooling\u2019. Amounting to the same thing, it\u2019s going to a beach that has rocks where the tide covers then uncovers little pools of water at different times of the day. All sorts of fun creatures and life can be found in this \u2018rocky intertidal habitat\u2019\nA particularly exciting creature that lives here is the Nudibranch, a type of super colourful \u2018sea slug\u2019. There are over 3000 species of Nudibranch worldwide. (The word \u201cnudibranch\u201d comes from the Latin nudus, naked, and the Greek \u03b2\u03c1\u03b1\u03bd\u03c7\u03b9\u03b1 / brankhia, gills.)\n\u200b\n\nThey are however quite tricky to find! Even though they are often brightly coloured and interestingly shaped, some of them are very small, and in our part of the world in the Bay Area in California their appearance in our rockpools is seasonal. We see them more often in Summer months, despite the not-as-low tides as in our Winter and Spring seasons.\nMy favourite place to go tidepooling here is Pillar Point in Half Moon bay (at other times of the year more famously known for the surf competition \u2018Mavericks\u2019). The rockpools there are rich in species diversity, of varied types and water-coverage habitat zones as well as being relatively accessible.\n\u200b\n\nI was rockpooling at Pillar Point recently with my parents and we talked to a lady who remarked that she hadn\u2019t seen any Nudibranchs on her visit this time. I realised that having an idea of what species to find where, and at what time of year is one of the many superpower goals of every budding Naturalist. \nUsing technology and the croudsourced species observations of the iNaturalist community we can shortcut our way to this superpower!\nFinding nearby animals with iNaturalist\nWe\u2019re going to be getting our information about what animals you can see in Pillar Point using iNaturalist. iNaturalist is a really fun platform that helps connect people to nature and report their findings of life in the outdoors. It is also a community of nature-loving people who help each other identify and confirm those observations. iNaturalist is a project run as a joint initiative by the California Academy of Sciences and the National Geographic Society.\nI\u2019ve been using iNaturalist for over two years to record and identify plants and animals that I\u2019ve found in the outdoors. I use their iPhone app to upload my pictures, which then uses machine learning algorithms to make an initial guess at what it is I\u2019ve seen. The community is really active, and I often find someone else has verified or updated my species guess pretty soon after posting. \nThis process is great because once an observation has been identified by at least two people it becomes \u2018verified\u2019 and is considered research grade. Research grade observations get exported and used by scientists, as well as being indexed by the Global Biodiversity Information Facility, GBIF.\n\u200b\n\niNaturalist has a great API and API explorer, which makes interacting and prototyping using iNaturalist data really fun. For example, if you go to the API explorer and expand the Observations : Search and fetch section and then the GET /observations API, you get a selection of input boxes that allow you to play with options that you can then pass to the API when you click the \u2018Try it out\u2019 button.\n\u200b\n\nYou\u2019ll then get a URL that looks a bit like\nhttps://api.inaturalist.org/v1/observations?captive=false &geo=true&verifiable=true&taxon_id=47113&lat=37.495461&lng=-122.499584 &radius=5&order=desc&order_by=created_at \nwhich you can call and interrrogate using a programming language of your choice.\nIf you would like to see an all-JavaScript application that uses the iNaturalist API, take a look at OwlsNearMe.com which Simon and I built one weekend earlier this year. It gets your location and shows you all iNaturalist observations of owls near you and lists which species you are likely to see (not adjusted for season).\nRapid development using Observable Notebooks\nWe\u2019re going to be using Observable Notebooks to prototype our examples, pulling data down from iNaturalist. I really like using visual notebooks like Observable, they are great for learning and building things quickly. You may be familiar with Jupyter notebooks for Python which is similar but takes a bit of setup to get going - I often use these for prototyping too. Observable is amazing for querying and visualising data with JavaScript and since it is a hosted product it doesn\u2019t require any setup at all.\nYou can follow along and play with this example on my Observable notebook. If you create an account there you can fork my notebook and create your own version of this example. \nEach \u2018notebook\u2019 consists of a page with a column of \u2018cells\u2019, similar to what you get in a spreadsheet. A cell can contain Markdown text or JavaScript code and the output of evaluating the cell appears above the code that generated it. There are lots of tutorials out there on Observable Notebooks, I like this code introduction one from Observable (and D3) creator Mike Bostock.\nDeveloping your Naturalist superpowers\nIf you have an idea of what plants and critters you might see in a place at the time you visit, you can hone in on what you want to study and train your Naturalist eye to better identify the life around you.\nFor our example, we care about wildlife we can see at Pillar Point, so we need a way of letting the iNaturalist API know which area we are interested in.\nWe could use a latitide, longitude and radius for this, but a rectangular bounding box is a better shape for the reef. We can use this tool to draw the area we want to search within: boundingbox.klokantech.com\n\u200b\n\nThe tool lets you export the bounding box in several forms using the dropdown at the bottom left under the map givese We are going to use the \u2018DublinCore\u2019 format as it\u2019s closest to the format needed by the iNaturalist API.\n westlimit=-122.50542; southlimit=37.492805; eastlimit=-122.492738; northlimit=37.499811\nA quick map primer:\nThe higher the latitude the more north it is\nThe lower the latitude the more south it is\nLatitude 0 = the equator\n\nThe higher the longitude the more east it is of Greenwich\nThe lower the longitude the more west it is of Greenwich\nLongitude 0 = Greenwich\nIn the iNaturalst API we want to use the parameters nelat, nelng, swlat, swlng to create a query that looks inside a bounding box of Pillar Point near Half Moon Bay in California:\nnelat = highest latitude = north limit = 37.499811\nnelng = highest longitude = east limit = -122.492738\nswlat = smallest latitude = south limit = 37.492805\nswlng = smallest longitude = west limit = 122.50542\nAs API parameters these look like this:\n?nelat=37.499811&nelng=-122.492738&swlat=37.492805&swlng=122.50542\nThese parameters in this format can be used for most of the iNaturalist API methods.\nNudibranch seasonality in Pillar Point\nWe can use the iNaturalist observation_histogram API to get a count of Nudibranch observations per week-of-year across all time and within our Pillar Point bounding box.\nIn addition to the geographic parameters that we just worked out, we are also sending the taxon_id of 47113, which is iNaturalists internal number associated with the Nudibranch taxon. By using this we can get all species which are under the parent \u2018Order Nudibranchia\u2019. \nAnother useful piece of naturalist knowledge is understanding the biological classification scheme of Taxanomic Rank - roughly, when a species has a Latin name of two words eg \u2018Glaucus Atlanticus\u2019 the first Latin word is the \u2018Genus\u2019 like a family name \u2018Glaucus\u2019, and the second word identifies that particular species, like a given name \u2018Atlanticus\u2019. \nThe two Latin words together indicate a specific species, the term we use colloquially to refer to a type of animal often differs wildly region to region, and sometimes the same common name in two countries can refer to two different species. The common names for the Glaucus Atlanticus (which incidentally is my favourite sea slug) include: sea swallow, blue angel, blue glaucus, blue dragon, blue sea slug and blue ocean slug! Because this gets super confusing, Scientists like using this Latin name format instead.\nThe following piece of code asks the iNaturalist Histogram API to return per-week counts for verified observations of Nudibranchs within our Pillar Point bounding box:\npillar_point_counts_per_week = fetch(\n  \"https://api.inaturalist.org/v1/observations/histogram?taxon_id=47113&nelat=37.499811&nelng=-122.492738&swlat=37.492805&swlng=-122.50542&date_field=observed&interval=week_of_year&verifiable=true\"\n  ).then(response => {\n  return response.json();\n})\nOur next step is to take this data and draw a graph! We\u2019ll be using Vega-Lite for this, which is a fab JavaScript graphing libary that is also easy and fun to use with Observable Notebooks. \n(Here is a great tutorial on exploring data and drawing graphs with Observable and Vega-Lite)\nThe iNaturalist API returns data that looks like this:\n{\n  \"total_results\": 53,\n  \"page\": 1,\n  \"per_page\": 53,\n  \"results\": {\n    \"week_of_year\": {\n      \"1\": 136,\n      \"2\": 20,\n      \"3\": 150,\n      \"4\": 65,\n      \"5\": 186,\n      \"6\": 74,\n      \"7\": 47,\n      \"8\": 87,\n      \"9\": 64,\n      \"10\": 56,\nBut for our Vega-Lite graph we need data that looks like this:\n[{\n  \"week\": \"01\",\n  \"value\": 136\n}, {\n  \"week\": \"02\",\n  \"value\": 20\n}, ...]\nWe can convert what we get back from the API to the second format using a loop that iterates over the object keys:\nobjects_to_plot = {\n  let objects = [];\n  Object.keys(pillar_point_counts_per_week.results.week_of_year).map(function(week_index) {\n    objects.push({\n      week: `Wk ${week_index.toString()}`,\n      observations: pillar_point_counts_per_week.results.week_of_year[week_index]\n    });\n  })\n  return objects;\n}\nWe can then plug this into Vega-Lite to draw us a graph:\nvegalite({\n  data: {values: objects_to_plot},\n  mark: \"bar\",\n  encoding: {\n    x: {field: \"week\", type: \"nominal\", sort: null},\n    y: {field: \"observations\", type: \"quantitative\"}\n  },\n  width: width * 0.9\n})\n\nIt\u2019s worth noting that we have a lot of observations of Nudibranchs particularly at Pillar Point due in no small part to the intertidal monitoring research that Alison Young and Rebecca Johnson facilitate for the California Achademy of Sciences. \nSo, what if we want to look for the seasonality of observations of a particular species of adorable sea slug? We want our interface to have a select box with a list of all the species you might find at any time of year. We can do this using the species_counts API to create us an object with the iNaturalist species ID and common & Latin names.\npillar_point_nudibranches = {\n  let api_results = await fetch(\n  \"https://api.inaturalist.org/v1/observations/species_counts?taxon_id=47113&nelat=37.499811&nelng=-122.492738&swlat=37.492805&swlng=-122.50542&date_field=observed&verifiable=true\"\n  ).then(r => r.json())\n\n  let species_list = api_results.results.map(i => ({\n      value: i.taxon.id,\n      label: `${i.taxon.preferred_common_name} (${i.taxon.name})`\n  }));\n\n  return species_list\n}\nWe can create an interactive select box by importing code from Jeremy Ashkanas\u2019 Observable Notebook: add import {select} from \"@jashkenas/inputs\" to a cell anywhere in our notebook. Observable is magic: like a spreadsheet, the order of the cells doesn\u2019t matter - if one cell is referenced by any other cell then when that cell updates all the other cells refresh themselves. You can also import and reference one notebook from another!\nviewof select_species = select({\n    title: \"Which Nudibranch do you want to see seasonality for?\",\n    options: [{value: \"\", label: \"All the Nudibranchs!\"}, ...pillar_point_nudibranches],\n    value: \"\"\n})\nThen we go back to our old favourite, the histogram API just like before, only this time we are calling it with the value created by our select box ${select_species} as taxon_id instead of the number 47113.\npillar_point_counts_per_month_per_species = fetch(\n  `https://api.inaturalist.org/v1/observations/histogram?taxon_id=${select_species}&nelat=37.499811&nelng=-122.492738&swlat=37.492805&swlng=-122.50542&date_field=observed&interval=month_of_year&verifiable=true`\n).then(r => r.json())\nNow for the fun graph bit! As we did before, we re-format the result of the API into a format compatible with Vega-Lite:\nobjects_to_plot_species_month = {\n  let objects = [];\n  Object.keys(pillar_point_counts_per_month_per_species.results.month_of_year).map(function(month_index) {\n    objects.push({\n      month: (new Date(2018, (month_index - 1), 1)).toLocaleString(\"en\", {month: \"long\"}),\n      observations: pillar_point_counts_per_month_per_species.results.month_of_year[month_index]\n    });\n  })\n  return objects;\n}\n(Note that in the above code we are creating a date object with our specific month in, and using toLocalString() to get the longer English name for the month. Because the JavaScript Date object counts January as 0, we use month_index -1 to get the correct month)\nAnd we draw the graph as we did before, only now if you interact with the select box in Observable the graph will dynamically update!\nvegalite({\n  data: {values: objects_to_plot_species_month},\n  mark: \"bar\",\n  encoding: {\n    x: {field: \"month\", type: \"nominal\", sort:null},\n    y: {field: \"observations\", type: \"quantitative\"}\n  },\n  width: width * 0.9\n})\nNow we can see when is the best time of year to plan to go tidepooling in Pillar Point if we want to find a specific species of Nudibranch.\n\u200b\n\nThis tool is great for planning when we to go rockpooling at Pillar Point, but what about if you are going this month and want to pre-train your eye with what to look for in order to impress your friends with your knowledge of Nudibranchs?\nWell\u2026 we can create ourselves a dynamic guide that you can with a list of the species, their photo, name and how many times they have been observed in that month of the year!\nOur select box this time looks as follows, simpler than before but assigning the month value to the variable selected_month.\nviewof selected_month = select({\n    title: \"When do you want to see Nudibranchs?\",\n    options: [\n      { label: \"Whenever\", value: \"\" },\n      { label: \"January\", value: \"1\" },\n      { label: \"February\", value: \"2\" },\n      { label: \"March\", value: \"3\" },\n      { label: \"April\", value: \"4\" },\n      { label: \"May\", value: \"5\" },\n      { label: \"June\", value: \"6\" },\n      { label: \"July\", value: \"7\" },\n      { label: \"August\", value: \"8\" },\n      { label: \"September\", value: \"9\" },\n      { label: \"October\", value: \"10\" },\n      { label: \"November\", value: \"11\" },\n      { label: \"December\", value: \"12\" },\n    ],\n    value: \"\"\n })\nWe then can use the species_counts API to get all the relevant information about which species we can see in month=${selected_month}. We\u2019ll be able to reference this response object and its values later with the variable we just created, eg: all_species_data.results[0].taxon.name.\nall_species_data = fetch(\n    `https://api.inaturalist.org/v1/observations/species_counts?taxon_id=47113&month=${selected_month}&nelat=37.499811&nelng=-122.492738&swlat=37.492805&swlng=-122.50542&verifiable=true`\n).then(r => r.json())\nYou can render HTML directly in a notebook cell using Observable\u2019s html tagged template literal:\n<style> \n.collection { margin-top: 2em }\n.collection .species { display: inline-block; width: 9em; margin-bottom: 2em; }\n.collection .species-name { font-size: 1em; margin: 0; padding: 0 } \n.collection .species-count { margin: 0 0 0.3em 0; padding: 0; font-size: 0.75em; color: #999; font-style: italic; }\n.collection img { display: block; width: 100% }\n.collection select { font-size: 1.5em; }\n</style>\n\n<h2>If you go to Pillar Point ${\n  {\"\": \"\",\n   \"1\":\"in January\",\n   \"2\":\"in Febrary\",\n   \"3\":\"in March\",\n   \"4\":\"in April\",\n   \"5\":\"in May\",\n   \"6\":\"in June\",\n   \"7\":\"in July\",\n   \"8\":\"in August\",\n   \"9\":\"in September\",\n   \"10\":\"in October\",\n   \"11\":\"in November\",\n   \"12\":\"in December\",\n  }[selected_month]\n } you might see\u2026</h2>\n\n<div class=\"collection\">\n${all_species_data.results.map(s => `<div class=\"species\"><h3 class=\"species-name\">${s.taxon.name}</h3>\n  <p class=\"species-count\">Seen ${s.count} times</p>\n  <img src=\"${s.taxon.default_photo.medium_url}\"></div>\n`)}\n</div>\nThese few lines of HTML are all you need to get this exciting dynamic guide to what Nudibranchs you will see in each month!\n\u200b\n\nPlay with it yourself in this Observable Notebook.\nConclusion\nI hope by playing with these examples you have an idea of how powerful it can be to prototype using Observable Notebooks and how you can use the incredible crowdsourced community data and APIs from iNaturalist to augment your naturalist skills and impress your friends with your new \u2018knowledge of nature\u2019 superpower.\nLastly I strongly encourage you to get outside on a low tide to explore your local rocky intertidal habitat, and all the amazing critters that live there.\nHere is a great introduction video to tidepooling / rockpooling, by Rebecca Johnson and Alison Young from the California Academy of Sciences.", "year": "2018", "author": "Natalie Downe", "author_slug": "nataliedowne", "published": "2018-12-18T00:00:00+00:00", "url": "https://24ways.org/2018/observable-notebooks-and-inaturalist/", "topic": "code"}
{"rowid": 257, "title": "The (Switch)-Case for State Machines in User Interfaces", "contents": "You\u2019re tasked with creating a login form. Email, password, submit button, done.\n\u201cThis will be easy,\u201d you think to yourself.\nLogin form by Selecto\nYou\u2019ve made similar forms many times in the past; it\u2019s essentially muscle memory at this point. You\u2019re working closely with a designer, who gives you a beautiful, detailed mockup of a login form. Sure, you\u2019ll have to translate the pixels to meaningful, responsive CSS values, but that\u2019s the least of your problems.\nAs you\u2019re writing up the HTML structure and CSS layout and styles for this form, you realize that you don\u2019t know what the successful \u201clogged in\u201d page looks like. You remind the designer, who readily gives it to you. But then you start thinking more and more about how the login form is supposed to work.\n\nWhat if login fails? Where do those errors show up?\nShould we show errors differently if the user forgot to enter their email, or password, or both?\nOr should the submit button be disabled?\nShould we validate the email field?\nWhen should we show validation errors \u2013 as they\u2019re typing their email, or when they move to the password field, or when they click submit? (Note: many, many login forms are guilty of this.)\nWhen should the errors disappear?\nWhat do we show during the login process? Some loading spinner?\nWhat if loading takes too long, or a server error occurs?\n\nMany more questions come up, and you (and your designer) are understandably frustrated. The lack of upfront specification opens the door to scope creep, which readily finds itself at home in all the unexplored edge cases.\nModeling Behavior\nDescribing all the possible user flows and business logic of an application can become tricky. Ironically, user stories might not tell the whole story \u2013 they often leave out potential edge-cases or small yet important bits of information.\nHowever, one important (and very old) mathematical model of computation can be used for describing the behavior and all possible states of a user interface: the finite state machine.\nThe general idea, as it applies to user interfaces, is that all of our applications can be described (at some level of abstraction) as being in one, and only one, of a finite number of states at any given time. For example, we can describe our login form above in these states:\n\nstart - not submitted yet\nloading - submitted and logging in\nsuccess - successfully logged in\nerror - login failed\n\nAdditionally, we can describe an application as accepting a finite number of events \u2013 that is, all the possible events that can be \u201csent\u201d to the application, either from the user or some other external entity:\n\nSUBMIT - pressing the submit button\nRESOLVE - the server responds, indicating that login is successful\nREJECT - the server responds, indicating that login failed\n\nThen, we can combine these states and events to describe the transitions between them. That is, when the application is in one state, an an event occurs, we can specify what the next state should be:\n\nFrom the start state, when the SUBMIT event occurs, the app should be in the loading state.\nFrom the loading state, when the RESOLVE event occurs, login succeeded and the app should be in the success state.\nIf login fails from the loading state (i.e., when the REJECT event occurs), the app should be in the error state.\nFrom the error state, the user should be able to retry login: when the SUBMIT event occurs here, the app should go to the loading state.\nOtherwise, if any other event occurs, don\u2019t do anything and stay in the same state.\n\nThat\u2019s a pretty thorough description, similar to a user story! It\u2019s also a bit more symbolic than a user story (e.g., \u201cwhen the SUBMIT event occurs\u201d instead of \u201cwhen the user presses the submit button\u201d), and that\u2019s for a reason. By representing states, events, and transitions symbolically, we can visualize what this state machine looks like:\n\nEvery state is represented by a box, and every event is connected to a transition arrow that connects two states. This makes it intuitive to follow the flow and understand what the next state should be given the current state and an event.\nFrom Visuals to Code\nDrawing a state machine doesn\u2019t require any special software; in fact, using paper and pencil (in case anything changes!) does the job quite nicely. However, one common problem is handoff: it doesn\u2019t matter how detailed a user story or how well-designed a visualization is, it eventually has to be coded in order for it to become part of a real application.\nWith the state machine model described above, the same visual description can be mapped directly to code. Traditionally, and as the title suggests, this is done using switch/case statements:\nfunction loginMachine(state, event) {\n    switch (state) {\n        case 'start':\n            if (event === 'SUBMIT') {\n                return 'loading';\n            }\n            break;\n        case 'loading':\n            if (event === 'RESOLVE') {\n                return 'success';\n            } else if (event === 'REJECT') {\n                return 'error';\n            }\n            break;\n        case 'success':\n            // Accept no further events\n            break;\n        case 'error':\n            if (event === 'SUBMIT') {\n                return 'loading';\n            }\n            break;\n        default:\n            // This should never occur\n            return undefined;\n    }\n}\n\nconsole.log(loginMachine('start', 'SUBMIT'));\n// => 'loading'\nThis is fine (I suppose) but personally, I find it much easier to use objects:\nconst loginMachine = {\n  initial: \"start\",\n  states: {\n    start: {\n      on: { SUBMIT: 'loading' }\n    },\n    loading: {\n      on: {\n        REJECT: 'error',\n        RESOLVE: 'success'\n      }\n    },\n    error: {\n      on: {\n        SUBMIT: 'loading'\n      }\n    },\n    success: {}\n  }\n};\n\nfunction transition(state, event) {\n  return machine\n    .states[state] // Look up the state\n    .on[event]     // Look up the next state based on the event\n    || state;      // If not found, return the current state\n}\n\nconsole.log(transition('start', 'SUBMIT'));\nAs you might have noticed, the loginMachine is a plain JS object, and can be written in JSON. This is important because it allows the machine to be visualized by a 3rd-party tool, as demonstrated here:\n\nA Common Language Between Designers and Developers\nAlthough finite state machines are a fundamental part of computer science, they have an amazing potential to bridge the application specification gap between designers and developers, as well as project managers, stakeholders, and more. By designing a state machine visually and with code, designers and developers alike can:\n\nidentify all possible states, and potentially missing states\ndescribe exactly what should happen when an event occurs on a given state, and prevent that event from having unintended side-effects in other states (ever click a submit button more than once?)\neliminate impossible states and identify states that are \u201cunreachable\u201d (have no entry transition) or \u201csunken\u201d (have no exit transition)\nadd features with full confidence of knowing what other states it might affect\nsimplify redundant states or complex user flows\ncreate test paths for almost every possible user flow, and easily identify edge cases\ncollaborate better by understanding the entire application model equally.\n\nNot a New Idea\nI\u2019m not the first to suggest that state machines can help bridge the gap between design and development.\n\nVince MingPu Shao wrote an article about designing UI states and communicating with developers effectively with finite state machines\nUser flow diagrams, which visually describe the paths that a user can take through an app to achieve certain goals, are essentially state machines. Numerous tools, from Sketch plugins to standalone apps, exist for creating them.\nIn 1999, Ian Horrocks wrote a book titled \u201cConstructing the User Interface with Statecharts\u201d, which takes state machines to the next level and describes the inherent difficulties (and solutions) with creating complex UIs. The ideas in the book are still relevant today.\nMore than a decade earlier, David Harel published \u201cStatecharts: A Visual Formalism for Complex Systems\u201d, in which the statechart - an extended hierarchical state machine model - is born.\n\nState machines and statecharts have been used for complex systems and user interfaces, both physical and digital, for decades, and are especially prevalent in other industries, such as game development and embedded electronic systems. Even NASA uses statecharts for the Curiosity Rover and more, citing many benefits:\n\nVisualized modeling\nPrecise diagrams\nAutomatic code generation\nComprehensive test coverage\nAccommodation of late-breaking requirements changes\n\nMoving Forward\nIt\u2019s time that we improve how we communicate between designers and developers, much less improve the way we develop UIs to deliver the best, bug-free, optimal user experience. There is so much more to state machines and statecharts than just being a different way of designing and coding. For more resources:\n\nThe World of Statecharts is a comprehensive guide by Erik Mogensen in using statecharts in your applications\nThe Statechart Community on Spectrum is always full of interesting ideas and questions related to state machines, statecharts, and software modeling\nI gave a talk at React Rally over a year ago about how state machines (finite automata) can improve the way we develop applications. The latest one is from Reactive Conf, where I demonstrate how statecharts can be used to automatically generate test cases.\nI have also been working on XState, which is a library for \u201cstate machines and statecharts for the modern web\u201d. You can create and visualize statecharts in JavaScript, and use them in any framework (and soon enough, multiple different languages).\n\nI\u2019m excited about the future of developing web and mobile applications with statecharts, especially with regard to faster design/development cycles, auto-generated testing, better error prevention, comprehensive analytics, and even the use of model-based reinforcement learning and artificial intelligence to greatly improve the user experience.", "year": "2018", "author": "David Khourshid", "author_slug": "davidkhourshid", "published": "2018-12-12T00:00:00+00:00", "url": "https://24ways.org/2018/state-machines-in-user-interfaces/", "topic": "code"}
{"rowid": 258, "title": "Mistletoe Offline", "contents": "It\u2019s that time of year, when we gather together as families to celebrate the life of the greatest person in history. This man walked the Earth long before us, but he left behind words of wisdom. Those words can guide us every single day, but they are at the forefront of our minds during this special season.\nI am, of course, talking about Murphy, and the golden rule he gave unto us:\n\nAnything that can go wrong will go wrong.\n\nSo true! I mean, that\u2019s why we make sure we\u2019ve got nice 404 pages. It\u2019s not that we want people to ever get served a File Not Found message, but we acknowledge that, despite our best efforts, it\u2019s bound to happen sometime. Murphy\u2019s Law, innit?\nBut there are some Murphyesque situations where even your lovingly crafted 404 page won\u2019t help. What if your web server is down? What if someone is trying to reach your site but they lose their internet connection? These are all things than can\u2014and will\u2014go wrong.\nI guess there\u2019s nothing we can do about those particular situations, right?\nWrong!\nA service worker is a Murphy-battling technology that you can inject into a visitor\u2019s device from your website. Once it\u2019s installed, it can intercept any requests made to your domain. If anything goes wrong with a request\u2014as is inevitable\u2014you can provide instructions for the browser. That\u2019s your opportunity to turn those server outage frowns upside down. Take those network connection lemons and make network connection lemonade.\nIf you\u2019ve got a custom 404 page, why not make a custom offline page too?\nGet your server in order\nStep one is to make \u2026actually, wait. There\u2019s a step before that. Step zero. Get your site running on HTTPS, if it isn\u2019t already. You won\u2019t be able to use a service worker unless everything\u2019s being served over HTTPS, which makes sense when you consider the awesome power that a service worker wields.\nIf you\u2019re developing locally, service workers will work fine for localhost, even without HTTPS. But for a live site, HTTPS is a must.\nMake an offline page\nAlright, assuming your site is being served over HTTPS, then step one is to create an offline page. Make it as serious or as quirky as is appropriate for your particular brand. If the website is for a restaurant, maybe you could put the telephone number and address of the restaurant on the custom offline page (unsolicited advice: you could also put this on the home page, you know). Here\u2019s an example of the custom offline page for this year\u2019s Ampersand conference.\nWhen you\u2019re done, publish the offline page at suitably imaginative URL, like, say /offline.html.\nPre-cache your offline page\nNow create a JavaScript file called serviceworker.js. This is the script that the browser will look to when certain events are triggered. The first event to handle is what to do when the service worker is installed on the user\u2019s device. When that happens, an event called install is fired. You can listen out for this event using addEventListener:\naddEventListener('install', installEvent => {\n// put your instructions here.\n}); // end addEventListener\nIn this case, you want to make sure that your lovingly crafted custom offline page is put into a nice safe cache. You can use the Cache API to do this. You get to create as many caches as you like, and you can call them whatever you want. Here, I\u2019m going to call the cache Johnny just so I can refer to it as JohnnyCache in the code:\naddEventListener('install', installEvent => {\n  installEvent.waitUntil(\n    caches.open('Johnny')\n    .then( JohnnyCache => {\n      JohnnyCache.addAll([\n       '/offline.html'\n      ]); // end addAll\n    }) // end open.then\n  ); // end waitUntil\n}); // end addEventListener\nI\u2019m betting that your lovely offline page is linking to a CSS file, maybe an image or two, and perhaps some JavaScript. You can cache all of those at this point:\naddEventListener('install', installEvent => {\n  installEvent.waitUntil(\n    caches.open('Johnny')\n    .then( JohnnyCache => {\n      JohnnyCache.addAll([\n       '/offline.html',\n       '/path/to/stylesheet.css',\n       '/path/to/javascript.js',\n           '/path/to/image.jpg'\n      ]); // end addAll\n    }) // end open.then\n  ); // end waitUntil\n}); // end addEventListener\nMake sure that the URLs are correct. If just one of the URLs in the list fails to resolve, none of the items in the list will be cached.\nIntercept requests\nThe next event you want to listen for is the fetch event. This is probably the most powerful\u2014and, let\u2019s be honest, the creepiest\u2014feature of a service worker. Once it has been installed, the service worker lurks on the user\u2019s device, waiting for any requests made to your site. Every time the user requests a web page from your site, a fetch event will fire. Every time that page requests a style sheet or an image, a fetch event will fire. You can provide instructions for what should happen each time:\naddEventListener('fetch', fetchEvent => {\n// What happens next is up to you!\n}); // end addEventListener\nLet\u2019s write a fairly conservative script with the following logic:\n\nWhenever a file is requested,\nFirst, try to fetch it from the network,\nBut if that doesn\u2019t work, try to find it in the cache,\nBut if that doesn\u2019t work, and it\u2019s a request for a web page, show the custom offline page instead.\n\nHere\u2019s how that translates into JavaScript:\n// Whenever a file is requested\naddEventListener('fetch', fetchEvent => {\n  const request = fetchEvent.request;\n  fetchEvent.respondWith(\n    // First, try to fetch it from the network\n    fetch(request)\n    .then( responseFromFetch => {\n      return responseFromFetch;\n    }) // end fetch.then\n    // But if that doesn't work\n    .catch( fetchError => {\n      // try to find it in the cache\n      caches.match(request)\n      .then( responseFromCache => {\n        if (responseFromCache) {\n         return responseFromCache;\n       // But if that doesn't work\n       } else {\n         // and it's a request for a web page\n         if (request.headers.get('Accept').includes('text/html')) {\n           // show the custom offline page instead\n           return caches.match('/offline.html');\n         } // end if\n       } // end if/else\n     }) // end match.then\n   }) // end fetch.catch\n  ); // end respondWith\n}); // end addEventListener\nI am fully aware that I may have done some owl-drawing there. If you need a more detailed breakdown of what\u2019s happening at each point in the code, I\u2019ve written a whole book for you. It\u2019s the perfect present for Murphymas.\nHook up your service worker script\nYou can publish your service worker script at /serviceworker.js but you still need to tell the browser where to look for it. You can do that using JavaScript. Put this in an existing JavaScript file that you\u2019re calling in to every page on your site, or add this in a script element at the end of every page\u2019s HTML:\nif (navigator.serviceWorker) {\n  navigator.serviceWorker.register('/serviceworker.js');\n}\nThat tells the browser to start installing the service worker, but not without first checking that the browser understands what a service worker is. When it comes to JavaScript, feature detection is your friend.\nYou might already have some JavaScript files in a folder like /assets/js/ and you might be tempted to put your service worker script in there too. Don\u2019t do that. If you do, the service worker will only be able to handle requests made to for files within /assets/js/. By putting the service worker script in the root directory, you\u2019re making sure that every request can be intercepted.\nGo further!\nNicely done! You\u2019ve made sure that if\u2014no, when\u2014a visitor can\u2019t reach your website, they\u2019ll get your hand-tailored offline page. You have temporarily defeated the forces of chaos! You have briefly fought the tide of entropy! You have made a small but ultimately futile gesture against the inevitable heat-death of the universe!\nThis is just the beginning. You can do more with service workers.\nWhat if, every time you fetched a page from the network, you stored a copy of that page in a cache? Then if that person tries to reach that page later, but they\u2019re offline, you could show them the cached version.\nOr, what if instead of reaching out the network first, you checked to see if a file is in the cache first? You could serve up that cached version\u2014which would be blazingly fast\u2014and still fetch a fresh version from the network in the background to pop in the cache for next time. That might be a good strategy for images.\nSo many options! The hard part isn\u2019t writing the code, it\u2019s figuring out the steps you want to take. Once you\u2019ve got those steps written out, then it\u2019s a matter of translating them into JavaScript.\nInevitably there will be some obstacles along the way\u2014usually it\u2019s a misplaced curly brace or a missing parenthesis. Don\u2019t be too hard on yourself if your code doesn\u2019t work at first. That\u2019s just Murphy\u2019s Law in action.", "year": "2018", "author": "Jeremy Keith", "author_slug": "jeremykeith", "published": "2018-12-04T00:00:00+00:00", "url": "https://24ways.org/2018/mistletoe-offline/", "topic": "code"}
{"rowid": 260, "title": "The Art of Mathematics: A Mandala Maker Tutorial", "contents": "In front-end development, there\u2019s often a great deal of focus on tools that aim to make our work more efficient. But what if you\u2019re new to web development? When you\u2019re just starting out, the amount of new material can be overwhelming, particularly if you don\u2019t have a solid background in Computer Science. But the truth is, once you\u2019ve learned a little bit of JavaScript, you can already make some pretty impressive things.\nA couple of years back, when I was learning to code, I started working on a side project. I wanted to make something colorful and fun to share with my friends. This is what my app looks like these days:\nMandala Maker user interface\nThe coolest part about it is the fact that it\u2019s a tool: anyone can use it to create something original and brand new. \nIn this tutorial, we\u2019ll build a smaller version of this app \u2013 a symmetrical drawing tool in ES5, JavaScript and HTML5. The tutorial app will have eight reflections, a color picker and a Clear button. Once we\u2019re done, you\u2019re on your own and can tweak it as you please. Be creative!\nPreparations: a blank canvas\nThe first thing you\u2019ll need for this project is a designated drawing space. We\u2019ll use the HTML5 canvas element and give it a width and a height of 600px (you can set the dimensions to anything else if you like).\nFiles\nCreate 3 files: index.html, styles.css, main.js. Don\u2019t forget to include your JS and CSS files in your HTML. \n<!DOCTYPE html>\n<html>\n<head>\n    <meta charset=\"utf-8\">\n    <link rel=\"stylesheet\" type=\"text/css\" href=\"style.css\">\n    <script src=\"main.js\"></script>\n</head>\n<body onload=\"init()\">\n    <canvas width=\"600\" height=\"600\">\n        <p>Your browser doesn't support canvas.</p>\n    </canvas>\n</body>\n</html>\nI\u2019ll ask you to update your HTML file at a later point, but the CSS file we\u2019ll start with will stay the same throughout the project. This is the full CSS we are going to use:\nbody {\n    background-color: #ccc;\n    text-align: center;\n}\n\ncanvas {\n    touch-action: none;\n    background-color: #fff;\n}\n\nbutton {\n    font-size: 110%;\n}\nNext steps\nWe are done with our preparations and ready to move on to the actual tutorial, which is made up of 4 parts:\n\nBuilding a simple drawing app with one line and one color \nAdding a Clear button and a color picker\nAdding more functionality: 2 line drawing (add the first reflection)\nAdding more functionality: 8 line drawing (add 6 more reflections!)\n\nInteractive demos\nThis tutorial will be accompanied by four CodePens, one at the end of each section. In my own app I originally used mouse events, and only added touch events when I realized mobile device support was (A) possible, and (B) going to make my app way more accessible. For the sake of code simplicity, I decided that in this tutorial app I will only use one event type, so I picked a third option: pointer events. These are supported by some desktop browsers and some mobile browsers. An up-to-date version of Chrome is probably your best bet.\nPart 1: A simple drawing app\nLet\u2019s get started with our main.js file. Our basic drawing app will be made up of 6 functions: init, drawLine, stopDrawing, recordPointerLocation, handlePointerMove, handlePointerDown. It also has nine variables:\nvar canvas, context, w, h,\n    prevX = 0, currX = 0, prevY = 0, currY = 0,\n    draw = false;\nThe variables canvas and context let us manipulate the canvas. w is the canvas width and h is the canvas height. The four coordinates are used for tracking the current and previous location of the pointer. A short line is drawn between (prevX, prevY) and (currX, currY) repeatedly many times while we move the pointer upon the canvas. For your drawing to appear, three conditions must be met: the pointer (be it a finger, a trackpad or a mouse) must be down, it must be moving and the movement has to be on the canvas. If these three conditions are met, the boolean draw is set to true. \n1. init\nResponsible for canvas set up, this listens to pointer events and the location of their coordinates and sets everything in motion by calling other functions, which in turn handle touch and movement events. \nfunction init() {\n    canvas = document.querySelector(\"canvas\");\n    context = canvas.getContext(\"2d\");\n    w = canvas.width;\n    h = canvas.height;\n\n    canvas.onpointermove = handlePointerMove;\n    canvas.onpointerdown = handlePointerDown;\n    canvas.onpointerup = stopDrawing;\n    canvas.onpointerout = stopDrawing;\n}\n2. drawLine\nThis is called to action by handlePointerMove() and draws the pointer path. It only runs if draw = true. It uses canvas methods you can read about in the canvas API documentation. You can also learn to use the canvas element in this tutorial.\nlineWidth and linecap set the properties of our paint brush, or digital pen, but pay attention to beginPath and closePath. Between those two is where the magic happens: moveTo and lineTo take canvas coordinates as arguments and draw from (a,b) to (c,d), which is to say from (prevX,prevY) to (currX,currY).\nfunction drawLine() {\n    var a = prevX,\n        b = prevY,\n        c = currX,\n        d = currY;\n\n    context.lineWidth = 4;\n    context.lineCap = \"round\";\n\n    context.beginPath();\n    context.moveTo(a, b);\n    context.lineTo(c, d);\n    context.stroke();\n    context.closePath();\n}\n3. stopDrawing\nThis is used by init when the pointer is not down (onpointerup) or is out of bounds (onpointerout).\nfunction stopDrawing() {\n    draw = false;\n}\n4. recordPointerLocation\nThis tracks the pointer\u2019s location and stores its coordinates. Also, you need to know that in computer graphics the origin of the coordinate space (0,0) is at the top left corner, and all elements are positioned relative to it. When we use canvas we are dealing with two coordinate spaces: the browser window and the canvas itself. This function converts between the two: it subtracts the canvas offsetLeft and offsetTop so we can later treat the canvas as the only coordinate space. If you are confused, read more about it.\nfunction recordPointerLocation(e) {\n    prevX = currX;\n    prevY = currY;\n    currX = e.clientX - canvas.offsetLeft;\n    currY = e.clientY - canvas.offsetTop;\n}\n5. handlePointerMove\nThis is set by init to run when the pointer moves. It checks if draw = true. If so, it calls recordPointerLocation to get the path and drawLine to draw it.\nfunction handlePointerMove(e) {\n    if (draw) {\n        recordPointerLocation(e);\n        drawLine();\n    }\n}\n6. handlePointerDown\nThis is set by init to run when the pointer is down (finger is on touchscreen or mouse it clicked). If it is, calls recordPointerLocation to get the path and sets draw to true. That\u2019s because we only want movement events from handlePointerMove to cause drawing if the pointer is down.\nfunction handlePointerDown(e) {\n    recordPointerLocation(e);\n    draw = true;\n}\nFinally, we have a working drawing app. But that\u2019s just the beginning!\nSee the Pen Mandala Maker Tutorial: Part 1 by Hagar Shilo (@hagarsh) on CodePen.\n\nPart 2: Add a Clear button and a color picker\nNow we\u2019ll update our HTML file, adding a menu div with an input of the type and class color and a button of the class clear.\n<body onload=\"init()\">\n    <canvas width=\"600\" height=\"600\">\n        <p>Your browser doesn't support canvas.</p>\n    </canvas>\n    <div class=\"menu\">\n        <input type=\"color\" class=\"color\" />\n        <button type=\"button\" class=\"clear\">Clear</button>\n    </div>\n</body>\nColor picker\nThis is our new color picker function. It targets the input element by its class and gets its value. \nfunction getColor() {\n    return document.querySelector(\".color\").value;\n}\nUp until now, the app used a default color (black) for the paint brush/digital pen. If we want to change the color we need to use the canvas property strokeStyle. We\u2019ll update drawLine by adding strokeStyle to it and setting it to the input value by calling getColor.\nfunction drawLine() {\n    //...code...  \n    context.strokeStyle = getColor();\n    context.lineWidth = 4;\n    context.lineCap = \"round\";\n\n    //...code...  \n}\nClear button\nThis is our new Clear function. It responds to a button click and displays a dialog asking the user if she really wants to delete the drawing.\nfunction clearCanvas() {\n    if (confirm(\"Want to clear?\")) {\n        context.clearRect(0, 0, w, h);\n    }\n}\nThe method clearRect takes four arguments. The first two (0,0) mark the origin, which is actually the top left corner of the canvas. The other two (w,h) mark the full width and height of the canvas. This means the entire canvas will be erased, from the top left corner to the bottom right corner. \nIf we were to give clearRect a slightly different set of arguments, say (0,0,w/2,h), the result would be different. In this case, only the left side of the canvas would clear up.\nLet\u2019s add this event handler to init:\nfunction init() {\n    //...code...\n    canvas.onpointermove = handleMouseMove;\n    canvas.onpointerdown = handleMouseDown;\n    canvas.onpointerup = stopDrawing;\n    canvas.onpointerout = stopDrawing;\n    document.querySelector(\".clear\").onclick = clearCanvas;\n}\nSee the Pen Mandala Maker Tutorial: Part 2 by Hagar Shilo (@hagarsh) on CodePen.\n\nPart 3: Draw with 2 lines\nIt\u2019s time to make a line appear where no pointer has gone before. A ghost line! \nFor that we are going to need four new coordinates: a', b', c' and d' (marked in the code as a_, b_, c_ and d_). In order for us to be able to add the first reflection, first we must decide if it\u2019s going to go over the y-axis or the x-axis. Since this is an arbitrary decision, it doesn\u2019t matter which one we choose. Let\u2019s go with the x-axis. \nHere is a sketch to help you grasp the mathematics of reflecting a point across the x-axis. The coordinate space in my sketch is different from my explanation earlier about the way the coordinate space works in computer graphics (more about that in a bit!). \nNow, look at A. It shows a point drawn where the pointer hits, and B shows the additional point we want to appear: a reflection of the point across the x-axis. This is our goal.\nA sketch illustrating the mathematics of reflecting a point.\nWhat happens to the x coordinates?\nThe variables a/a' and c/c' correspond to prevX and currX respectively, so we can call them \u201cthe x coordinates\u201d. We are reflecting across x, so their values remain the same, and therefore a' = a and c' = c. \nWhat happens to the y coordinates?\nWhat about b' and d'? Those are the ones that have to change, but in what way? Thanks to the slightly misleading sketch I showed you just now (of A and B), you probably think that the y coordinates b' and d' should get the negative values of b and d respectively, but nope. This is computer graphics, remember? The origin is at the top left corner and not at the canvas center, and therefore we get the following values: b = h - b, d' = h - d, where h is the canvas height.\nThis is the new code for the app\u2019s variables and the two lines: the one that fills the pointer\u2019s path and the one mirroring it across the x-axis.\nfunction drawLine() {\n    var a = prevX, a_ = a,\n        b = prevY, b_ = h-b,\n        c = currX, c_ = c,\n        d = currY, d_ = h-d;\n\n    //... code ...\n\n    // Draw line #1, at the pointer's location\n    context.moveTo(a, b);\n    context.lineTo(c, d);\n\n    // Draw line #2, mirroring the line #1\n    context.moveTo(a_, b_);\n    context.lineTo(c_, d_);\n\n    //... code ...\n}\nIn case this was too abstract for you, let\u2019s look at some actual numbers to see how this works.\nLet\u2019s say we have a tiny canvas of w = h = 10. Now let a = 3, b = 2, c = 4 and d = 3.\nSo b' = 10 - 2 = 8 and d' = 10 - 3 = 7.\nWe use the top and the left as references. For the y coordinates this means we count from the top, and 8 from the top is also 2 from the bottom. Similarly, 7 from the top is 3 from the bottom of the canvas. That\u2019s it, really. This is how the single point, and a line (not necessarily a straight one, by the way) is made up of many, many small segments that are similar to point in behavior.\nIf you are still confused, I don\u2019t blame you. \nHere is the result. Draw something and see what happens.\nSee the Pen Mandala Maker Tutorial: Part 3 by Hagar Shilo (@hagarsh) on CodePen.\n\nPart 4: Draw with 8 lines\nI have made yet another confusing sketch, with points C and D, so you understand what we\u2019re trying to do. Later on we\u2019ll look at points E, F, G and H as well. The circled point is the one we\u2019re adding at each particular step. The circled point at C has the coordinates (-3,2) and the circled point at D has the coordinates (-3,-2). Once again, keep in mind that the origin in the sketches is not the same as the origin of the canvas. \nA sketch illustrating points C and D.\nThis is the part where the math gets a bit mathier, as our drawLine function evolves further. We\u2019ll keep using the four new coordinates: a', b', c' and d', and reassign their values for each new location/line. Let\u2019s add two more lines in two new locations on the canvas. Their locations relative to the first two lines are exactly what you see in the sketch above, though the calculation required is different (because of the origin points being different).\nfunction drawLine() {\n\n    //... code ... \n\n    // Reassign values\n    a_ = w-a; b_ = b;\n    c_ = w-c; d_ = d;\n\n    // Draw the 3rd line\n    context.moveTo(a_, b_);\n    context.lineTo(c_, d_);\n\n    // Reassign values\n    a_ = w-a; b_ = h-b;\n    c_ = w-c; d_ = h-d;\n\n    // Draw the 4th line\n    context.moveTo(a_, b_);\n    context.lineTo(c_, d_);\n\n    //... code ... \nWhat is happening?\nYou might be wondering why we use w and h as separate variables, even though we know they have the same value. Why complicate the code this way for no apparent reason? That\u2019s because we want the symmetry to hold for a rectangular canvas as well, and this way it will. \nAlso, you may have noticed that the values of a' and c' are not reassigned when the fourth line is created. Why write their value assignments twice? It\u2019s for readability, documentation and communication. Maintaining the quadruple structure in the code is meant to help you remember that all the while we are dealing with two y coordinates (current and previous) and two x coordinates (current and previous). \nWhat happens to the x coordinates?\nAs you recall, our x coordinates are a (prevX) and c (currX).\nFor the third line we are adding, a' = w - a and c' = w - c, which means\u2026\nFor the fourth line, the same thing happens to our x coordinates a and c.\nWhat happens to the y coordinates?\nAs you recall, our y coordinates are b (prevY) and d (currY).\nFor the third line we are adding, b' = b and d' = d, which means the y coordinates are the ones not changing this time, making this is a reflection across the y-axis. \nFor the fourth line, b' = h - b and d' = h - d, which we\u2019ve seen before: that\u2019s a reflection across the x-axis.\nWe have four more lines, or locations, to define. Note: the part of the code that\u2019s responsible for drawing a micro-line between the newly calculated coordinates is always the same:\n    context.moveTo(a_, b_);\n    context.lineTo(c_, d_);\nWe can leave it out of the next code snippets and just focus on the calculations, i.e, the reassignments. \nOnce again, we need some concrete examples to see where we\u2019re going, so here\u2019s another sketch! The circled point E has the coordinates (2,3) and the circled point F has the coordinates (2,-3). The ability to draw at A but also make the drawing appear at E and F (in addition to B, C and D that we already dealt with) is the functionality we are about to add to out code.\nA sketch illustrating points E and F.\nThis is the code for E and F:\n    // Reassign for 5\n    a_ = w/2+h/2-b; b_ = w/2+h/2-a;\n    c_ = w/2+h/2-d; d_ = w/2+h/2-c;\n\n    // Reassign for 6\n    a_ = w/2+h/2-b; b_ = h/2-w/2+a;\n    c_ = w/2+h/2-d; d_ = h/2-w/2+c;\nTheir x coordinates are identical and their y coordinates are reversed to one another.\nThis one will be out final sketch. The circled point G has the coordinates (-2,3) and the circled point H has the coordinates (-2,-3).\nA sketch illustrating points G and H.\nThis is the code:\n    // Reassign for 7\n    a_ = w/2-h/2+b; b_ = w/2+h/2-a;\n    c_ = w/2-h/2+d; d_ = w/2+h/2-c;\n\n    // Reassign for 8\n    a_ = w/2-h/2+b; b_ = h/2-w/2+a;\n    c_ = w/2-h/2+d; d_ = h/2-w/2+c;\n    //...code...  \n}\nOnce again, the x coordinates of these two points are the same, while the y coordinates are different. And once again I won\u2019t go into the full details, since this has been a long enough journey as it is, and I think we\u2019ve covered all the important principles. But feel free to play around with the code and change it. I really recommend commenting out the code for some of the points to see what your drawing looks like without them.\nI hope you had fun learning! This is our final app:\nSee the Pen Mandala Maker Tutorial: Part 4 by Hagar Shilo (@hagarsh) on CodePen.", "year": "2018", "author": "Hagar Shilo", "author_slug": "hagarshilo", "published": "2018-12-02T00:00:00+00:00", "url": "https://24ways.org/2018/the-art-of-mathematics/", "topic": "code"}
{"rowid": 263, "title": "Securing Your Site like It\u2019s 1999", "contents": "Running a website in the early years of the web was a scary business. The web was an evolving medium, and people were finding new uses for it almost every day. From book stores to online auctions, the web was an expanding universe of new possibilities.\nAs the web evolved, so too did the knowledge of its inherent security vulnerabilities. Clever tricks that were played on one site could be copied on literally hundreds of other sites. It was a normal sight to log in to a website to find nothing working because someone had breached its defences and deleted its database. Lessons in web security in those days were hard-earned.\nWhat follows are examples of critical mistakes that brought down several early websites, and how you can help protect yourself and your team from the same fate.\nBad input validation: Trusting anything the user sends you\nOur story begins in the most unlikely place: Animal Crossing. Animal Crossing was a 2001 video game set in a quaint town, filled with happy-go-lucky inhabitants that co-exist peacefully. Like most video games, Animal Crossing was the subject of many fan communities on the early web.\nOne such unofficial web forum was dedicated to players discussing their adventures in Animal Crossing. Players could trade secrets, ask for help, and share pictures of their virtual homes. This might sound like a model community to you, but you would be wrong.\nOne day, a player discovered a hidden field in the forum\u2019s user profile form. Normally, this page allows users to change their name, their password, or their profile photo. This person discovered that the hidden field contained their unique user ID, which identifies them when the forum\u2019s backend saves profile changes to its database. They discovered that by modifying the form to change the user ID, they could make changes to any other player\u2019s profile.\nNeedless to say, this idyllic online community descended into chaos. Users changed each other\u2019s passwords, deleted each other\u2019s messages, and attacked each-other under the cover of complete anonymity. What happened?\nThere aren\u2019t any official rules for developing software on the web. But if there were, my golden rule would be:\nNever trust user input. Ever.\nAlways ask yourself how users will send you data that isn\u2019t what it seems to be. If the nicest community of gamers playing the happiest game on earth can turn on each other, nowhere on the web is safe.\nMake sure you validate user input to make sure it\u2019s of the correct type (e.g. string, number, JSON string) and that it\u2019s the length that you were expecting. Don\u2019t forget that user input doesn\u2019t become safe once it is stored in your database; any data that originates from outside your network can still be dangerous and must be escaped before it is inserted into HTML.\nMake sure to check a user\u2019s actions against what they are allowed to do. Create a clear access control policy that defines what actions a user may take, and to whose data they are allowed access to. For example, a newly-registered user should not be allowed to change the user profile of a web forum\u2019s owner.\nFinally, never rely on client-side validation. Validating user input in the browser is a convenience to the user, not a security measure. Always assume the user has full control over any data sent from the browser and make sure you validate any data sent to your backend from the outside world.\nSQL injection: Allowing the user to run their own database queries\nA long time ago, my favourite website was a web forum dedicated to the Final Fantasy video game series. Like the users of the Animal Crossing forum, I\u2019d while away many hours arguing with other people on the internet about my favourite characters, my favourite stories, and the greatest controversies of the day.\nOne day, I noticed people were acting strangely. Users were being uncharacteristically nasty and posting in private areas of the forum they wouldn\u2019t normally have access to. Then messages started disappearing, and user accounts for well-respected people were banned.\nIt turns out someone had discovered a way of logging in to any other user account, using a secret password that allowed them to do literally anything they wanted. What was this password that granted untold power to those who wielded it?\n' OR '1'='1\nSQL is a computer language that is used to query databases. When you fill out a login form, just like the one above, your username and your password are usually inserted into an SQL query like this:\n\nSELECT COUNT(*)\nFROM USERS\nWHERE USERNAME='Alice'\nAND PASSWORD='hunter2'\nThis query selects users from the database that match the username Alice and the password hunter2. If there is at least one user matching record, the user will be granted access. Let\u2019s see what happens when we use our magic password instead!\n\nSELECT COUNT(*)\nFROM USERS\nWHERE USERNAME='Admin'\nAND PASSWORD='' OR '1'='1'\nDoes the password look like part of the query to you? That\u2019s because it is! This password is a deliberate attempt to inject our own SQL into the query, hence the term SQL injection. The query is now looking for users matching the username Admin, with a password that is blank, or 1=1. In an SQL query, 1=1 is always true, which makes this query select every single record in the database. As long as the forum software is checking for at least one matching user, it will grant the person logging in access. This password will work for any user registered on the forum!\nSo how can you protect yourself from SQL injection?\nNever build SQL queries by concatenating strings. Instead, use parameterised query tools. PHP offers prepared statements, and Node.JS has the knex package. Alternatively, you can use an ORM tool, such as Propel or sequelize.\nExpert help in the form of language features or software tools is a key ally for securing your code. Get all the help you can!\nCross site request forgery: Getting other users to do your dirty work for you\nDo you remember Netflix? Not the Netflix we have now, the Netflix that used to rent you DVDs by mailing them to you. My next story is about how someone managed to convince Netflix users to send him their DVDs - free of charge.\nHave you ever clicked on a hyperlink, only to find something that you weren\u2019t expecting? If you were lucky, you might have just gotten Rickrolled. If you were unlucky\u2026\nLet\u2019s just say there are older and fouler things than Rick Astley in the dark places of the web.\nWhat if you could convince people to visit a page you controlled? And what if those people were Netflix users, and they were logged in? In 2006, Dave Ferguson did just that. He created a harmless-looking page with an image on it:\n<img src=\"http://www.netflix.com/JSON/AddToQueue?movieid=70110672\" />\nDid you notice the source URL of the image? It\u2019s deliberately crafted to add a particular DVD to your queue. Sprinkle in a few more requests to change the user\u2019s name and shipping address, and you could ship yourself DVDs completely free of charge!\nThis attack is possible when websites unconditionally trust a user\u2019s session cookies without checking where HTTP requests come from.\nThe first check you can make is to verify that a request\u2019s origin and referer headers match the location of the website. These headers can\u2019t be programmatically set.\nAnother check you can use is to add CSRF tokens to your web forms, to verify requests have come from an actual form on your website. Tokens are long, unpredictable, unique strings that are generated by your server and inserted into web forms. When users complete a form, the form data sent to the server can be checked for a recently generated token. This is an effective deterrent of CSRF attacks because CSRF tokens aren\u2019t stored in cookies.\nYou can also set SameSite=Strict when setting cookies with the Set-Cookie HTTP header. This communicates to browsers that cookies are not to be sent with cross-site requests. This is a relatively new feature, though it is well supported in evergreen browsers.\nCross site scripting: Someone else\u2019s code running on your website\nIn 2005, Samy Kamkar became famous for having lots of friends. Lots and lots of friends.\nSamy enjoyed using MySpace which, at the time, was the world\u2019s largest social network. Social networks at that time were more limited than today. For instance, MySpace let you upload photos to your photo gallery, but capped the limit at twelve. Twelve photos. At least you didn\u2019t have to wade through photos of avocado toast back then\u2026\nSamy discovered that MySpace also locked down the kinds of content that you could post on your MySpace page. He discovered he could inject <img /> and <div /> tags into his headline, but <script /> was filtered. MySpace wasn\u2019t about to let someone else run their own code on MySpace.\nIntrigued, Samy set about finding out exactly what he could do with <img /> and <div /> tags. He found that you could add style properties to <div /> tags to style them with CSS.\n<div style=\"background:url('javascript:alert(1)')\">\nThis code only worked in Internet Explorer and in some versions of Safari, but that was plenty of people to befriend. However, MySpace was prepared for this: they also filtered the word javascript from <div />.\n<div style=\"background:url('java\nscript:alert(1)')\">\nSamy discovered that by inserting a line break into his code, MySpace would not filter out the word javascript. The browser would continue to run the code just fine! Samy had now broken past MySpace\u2019s first line of defence and was able to start running code on his profile page. Now he started looking at what he could do with that code.\nalert(document.body.innerHTML)\nSamy wondered if he could inspect the page\u2019s source to find the details of other MySpace users to befriend. To do this, you would normally use document.body.innerHTML, but MySpace had filtered this too.\nalert(eval('document.body.inne' + 'rHTML'))\nThis isn\u2019t a problem if you build up JavaScript code inside a string and execute it using the eval() function. This trick also worked with XMLHttpRequest.onReadyStateChange, which allowed Samy to send friend requests to the MySpace API and install the JavaScript code on his new friends\u2019 pages.\nOne final obstacle stood in his way. The same origin policy is a security mechanism that prevents scripts hosted on one domain interacting with sites hosted on another domain.\nif (location.hostname == 'profile.myspace.com') {\n  document.location = 'http://www.myspace.com'\n  + location.pathname + location.search\n}\nSamy discovered that only the http://www.myspace.com domain would accept his API requests, and requests from http://profile.myspace.com were being blocked by the browser\u2019s same-origin policy. By redirecting the browser to http://www.myspace.com, he discovered that he could load profile pages and successfully make requests to MySpace\u2019s API. Samy installed this code on his profile page, and he waited.\n\nOver the course of the next day, over a million people unwittingly installed Samy\u2019s code into their MySpace profile pages and invited their friends. The load of friend requests on MySpace was so large that the site buckled and shut down. It took them two hours to remove Samy\u2019s code and patch the security holes he exploited. Samy was raided by the United States secret service and sentenced to do 90 days of community service.\nThis is the power of installing a little bit of JavaScript on someone else\u2019s website. It is called cross site scripting, and its effects can be devastating. It is suspected that cross-site scripting was to blame for the 2018 British Airways breach that leaked the credit card details of 380,000 people.\nSo how can you help protect yourself from cross-site scripting?\nAlways sanitise user input when it comes in, using a library such as sanitize-html. Open source tools like this benefit from hundreds of hours of work from dozens of experienced contributors. Don\u2019t be tempted to roll your own protection. MySpace was prepared, but they were not prepared enough. It makes no sense to turn this kind of help down.\nYou can also use an auto-escaping templating language to make sure nobody else\u2019s HTML can get into your pages. Both Angular and React will do this for you, and they are extremely convenient to use.\nYou should also implement a content security policy to restrict the domains that content like scripts and stylesheets can be loaded from. Loading content from sites not under your control is a significant security risk, and you should use a CSP to lock this down to only the sources you trust. CSP can also block the use of the eval() function.\nFor content not under your control, consider setting up sub-resource integrity protection. This allows you to add hashes to stylesheets and scripts you include on your website. Hashes are like fingerprints for digital files; if the content changes, so does the fingerprint. Adding hashes will allow your browser to keep your site safe if the content changes without you knowing.\nnpm audit: Protecting yourself from code you don\u2019t own\nJavaScript and npm run the modern web. Together, they make it easy to take advantage of the world\u2019s largest public registry of open source software. How do you protect yourself from code written by someone you\u2019ve never met? Enter npm audit.\nnpm audit reviews the security of your website\u2019s dependency tree. You can start using it by upgrading to the latest version of npm:\nnpm install npm -g\nnpm audit\nWhen you run npm audit, npm submits a description of your dependencies to the Registry, which returns a report of known vulnerabilities for the packages you have installed.\n\nIf your website has a known cross-site scripting vulnerability, npm audit will tell you about it. What\u2019s more, if the vulnerability has been patched, running npm audit fix will automatically install the patched package for you!\nSecuring your site like it\u2019s 2019\nThe truth is that since the early days of the web, the stakes of a security breach have become much, much higher. The web is so much more than fandom and mailing DVDs - online banking is now mainstream, social media and dating websites store intimate information about our personal lives, and we are even inviting the internet into our homes.\nHowever, we have powerful new allies helping us stay safe. There are more resources than ever before to teach us how to write secure code. Tools like Angular and React are designed with security features baked-in from the start. We have a new generation of security tools like npm audit to watch over our dependencies.\nAs we roll over into 2019, let\u2019s take the opportunity to reflect on the security of the code we write and be grateful for the everything we\u2019ve learned in the last twenty years.", "year": "2018", "author": "Katie Fenn", "author_slug": "katiefenn", "published": "2018-12-01T00:00:00+00:00", "url": "https://24ways.org/2018/securing-your-site-like-its-1999/", "topic": "code"}
{"rowid": 264, "title": "Dynamic Social Sharing Images", "contents": "Way back when social media was new, you could be pretty sure that whatever you posted would be read by those who follow you. If you\u2019d written a blog post and you wanted to share it with those who follow you, you could post a link and your followers would see it in their streams. Oh heady days! \nWith so many social channels and a proliferation of content and promotions flying past in everyone\u2019s streams, it\u2019s no longer enough to share content on social media, you have to actively sell it if you want it to be seen. You really need to make the most of every opportunity to catch a reader\u2019s attention if you\u2019re trying to get as many eyes as possible on that sweet, sweet social content.\nOne of the best ways to grab attention with your posts or tweets is to include an image. There\u2019s heaps of research that says that having images in your posts helps them stand out to followers. Reports I found showed figures from anything from 35% to 150% improvement from just having image in a post. Unfortunately, the details were surrounded with gross words like engagement and visual marketing assets and so I had to close the page before I started to hate myself too much.\nSo without hard stats to quote, we\u2019ll call it a rule of thumb. The rule of thumb is that posts with images will grab more attention than those without, so it makes sense that when adding pages to a website, you should make sure that they have social media sharing images associated with them.\nAdding sharing images\nThe process for declaring an image to be used in places like Facebook and Twitter is very simple, and at this point is familiar to many of us. You add a meta tag to the head of the page to point to the location of the image to use. When a link to the page is added to a post, the social network will fetch the page, look for the meta tag and then use the image you specified.\n<meta property=\"og:image\" content=\"https://example.com/my_image.jpg\">\nThere\u2019s a good post on this over at CSS-Tricks if you need to bone up on the details of this and other similar meta tags for social media sharing.\nThis is all fine and well for content that has a very obvious choice of image to go along with it, but what if you don\u2019t necessarily have an image? One approach is to use stock photography, but that\u2019s not going to be right for every situation.\nThis was something we faced with 24 ways in 2017. We wanted to add images to the tweets we post each day announcing a new article. Some articles have images, but not all, and there tended not to be any consistency in terms of imagery from one article to the next. We always have an author photograph, but those don\u2019t usually lend themselves directly to being the main \u2018hero\u2019 image for an article.\nPutting his thinking cap on, Paul came up with a design for an image that used the author photo along with a quote extracted from the article.\nOne of the hand-made sharing images from 2017\nEach day we would pick a quote from the article, and Paul would manually compose an image to be uploaded to the site. The results were great, but the whole process was a bit too labour intensive and relied on an individual (Paul) being available each day to do the work. I thought we could probably improve this.\nHatching a new plan\nOne initial idea I came up with was to script the image editor to dynamically build a new image by pulling content from our database. Sketch has plugins available to pull JSON content into a design, and our CMS can easily output JSON data, so that was one possibility.\nThe more I thought about this and how much I wish graphic design tools worked just a little bit more like CSS, the obvious solution hit me. We should just build it with CSS!\nIn fact, as the author name and image already exist in our CMS, and the visual styling is based on the design of the website, couldn\u2019t this just be another page on the site generated by the CMS?\nBreaking it down, I figured the steps needed would be something like:\n\nCreate the CSS to lay out a component that could be turned into an image\nAdd a new field to articles in the CMS to hold a handpicked quote\nBuild a new article template in the CMS to output the author name and quote dynamically for any article\n\u2026 um \u2026 screenshot?\n\nI thought I\u2019d get cracking and see if I could figure out the final steps later.\nBuilding the page\nThe first thing to tackle was the basic HTML and CSS to lay out the components for our image. That bit was really easy, as I just asked Paul to do it. Everyone should have a Paul.\nPaul\u2019s code uses a fixed dimension container in the HTML, set to 600 \u00d7 315px. This is to make it the correct aspect ratio for Facebook\u2019s recommended image size. It\u2019s useful to remember here that it doesn\u2019t need to be responsive or robust, as the page only needs to lay out correctly for a screenshot and a fixed size in a known browser.\nWith the markup and CSS in place, I turned this into a new template. Our CMS can easily display content through any number of templates, so I created a version of the article template that was totally stripped down. It only included the author details and the quote, along with Paul\u2019s markup.\nI also added the quote as a new field on the article in the CMS, so each \u2018image\u2019 could be quickly and easily customised in the editing process.\nI added a new field to the article template to capture the quote.\nWith very little effort, we quickly had a page to dynamically generate our \u2018image\u2019 right from the CMS. You can see any of them by adding /sharing onto the end of an article URL for any 2018 article.\nOur automatically generated layout direct from the CMS\nIt soon became clear that the elusive Step 4 was going to be the tricky part. I can create a small page on the site that looks like an image, but how should I go about turning it into one? An obvious route is to screenshot the page by hand, but that\u2019s going back to some of the manual steps I was trying to eliminate, and also opens up a possibility for errors to be made. But it did lead me to the thought\u2026 how could I automatically take a screenshot?\nEnter Puppeteer\nPuppeteer is a Node.js library that provides a nice API onto Headless Chrome. What is Headless Chrome, you ask? It\u2019s just a version of the Chrome browser than runs from the command line without ever drawing anything to a user interface window. It loads pages, renders CSS, runs JavaScript, pretty much every normal thing that Chrome on the desktop does, but without a clicky user interface.\nHeadless Chrome can be used for all sorts of things such as running automated tests on front-end code after making changes, or\u2026 get this\u2026 rendering pages that can be used for screenshots. The actual process of writing some code to control Chrome and to take the screenshot is where Puppeteer comes in. Puppeteer puts a friendly layer in front of big old scary Chrome to enable us to interact with it using simple JavaScript code running in Node.\nUsing Puppeteer, I can write a small script that will repeatably turn a URL into an image. So simple is it to do this, that\u2019s it\u2019s actually Puppeteer\u2019s \u2018hello world\u2019 example.\nFirst you install Puppeteer. It downloads a compatible headless browser (actually Chromium) as a dependancy, so you don\u2019t need to worry about installing that. At the command line:\nnpm i puppeteer\nThen save a new file as example.js with this code:\nconst puppeteer = require('puppeteer');\n\n(async () => {\n  const browser = await puppeteer.launch();\n  const page = await browser.newPage();\n  await page.goto('https://example.com');\n  await page.screenshot({path: 'example.png'});\n  await browser.close();\n})();\nand then run it using Node:\nnode example.js\nThis will output an image file example.png to disk, which contains a screenshot of, in this case https://example.com. The logic of the code is reasonably easy to follow:\n\nLaunch a browser\nOpen up a new page\nGoto a URL\nTake a screenshot\nClose the browser\n\nThe async function and await keywords are a way to have the script pause and wait for normally asynchronous code to return before proceeding. That\u2019s useful with actions like loading a web page that might take some time to complete. They\u2019re used with Promises, and the effect is to make asynchronous code behave as if it\u2019s synchronous. You can read more about async and await at MDN if you\u2019re interested.\nThat\u2019s a good proof-of-concept using the basic Puppeteer example. I can take a screenshot of a URL! But what happens if I put the URL of my new special page in there?\nOur content is up in the corner of the image with lots of empty space.\nThat\u2019s not great. It\u2019s okay, but not great. It looks like that, by default, Puppeteer takes a screenshot with a resolution of 800 \u00d7 600, so we need to find out how to adjust that. Fortunately, the docs aren\u2019t the worst and I was able to find the page.setViewport() method pretty easily.\nconst puppeteer = require('puppeteer');\n\n(async () => {\n  const browser = await puppeteer.launch();\n  const page = await browser.newPage();\n  await page.goto('https://24ways.org/2018/clip-paths-know-no-bounds/sharing');\n  await page.setViewport({\n    width: 600,\n    height: 315\n  });\n  await page.screenshot({path: 'example.png'});\n  await browser.close();\n})();\nThis worked! The screenshot is now 600 \u00d7 315 as expected. That\u2019s exactly what we asked for. Trouble is, that\u2019s a bit low res and it is nearly 2019 after all. While in those docs, I noticed the deviceScaleFactor option that can be passed to page.setViewport(). Setting that to 2 gives us an image of the same area of the screen, but with twice as many pixels.\n  await page.setViewport({\n    width: 600,\n    height: 315,\n    deviceScaleFactor: 2\n  });\nPerfect! We now have a programmatic way of turning a URL into an image.\nImproving the script\nRather than having a script with a fixed URL in it that outputs an image called example.png, the next step is to make that a bit more dynamic. The aim here is to have a script that we can run with a URL as an argument and have it output an image for that one page. That way we can run it manually, or hook it into part of our site\u2019s build process to automate the generation of the image.\nOur goal is to call the script like this:\nnode shoot-sharing-image.js https://24ways.org/2018/clip-paths-know-no-bounds/\nAnd I want the image to come out with the name clip-paths-know-no-bounds.png. To do that, I need to have my script look for command arguments, and then to split the URL up to grab the slug from it.\n// Get the URL and the slug segment from it\nconst url = process.argv[2];\nconst segments = url.split('/');\n// Get the second-to-last segment (the slug)\nconst slug = segments[segments.length-2];\nWe can then use these variables later in the script, remembering to add sharing back onto the end of the URL to get our dedicated page.\n(async () => {\n  const browser = await puppeteer.launch();\n  const page = await browser.newPage();\n  await page.goto(url + 'sharing');\n  await page.setViewport({\n    width: 600,\n    height: 315,\n    deviceScaleFactor: 2\n  });\n  await page.screenshot({path: slug + '.png'});\n  await browser.close();\n})();\nOnce you\u2019re generating the image with Node, there\u2019s all sorts of things you can do with it. An obvious step is to move it to the correct location within your site or project.\nYou can also run optimisations on the file. I\u2019m using imagemin with pngquant to reduce the file size a little.\nconst imagemin = require('imagemin');\nconst imageminPngquant = require('imagemin-pngquant');\n\nawait imagemin([slug + '.png'], 'build', {\n  plugins: [\n    imageminPngquant({quality: '75-90'})\n  ]\n});\n\nYou can see the completed example as a gist.\nIntegrating it with your CMS\nSo we now have a command we can run to take a URL and generate a custom image for that URL. It\u2019s in a format that can be called by any sort of build script, or triggered from a publishing hook in a CMS. Exactly how you do that is going to depend on the way your site is built and the technology stack you\u2019re using, but it\u2019s likely not too hard as long as you can run a command as part of the process.\nFor 24 ways this year, I\u2019ve been running the script by hand once each article is ready. My script adds the file to a git repo and pushes to a deployment remote that is configured to automatically deploy static assets to our server. Along with our theme of making incremental improvements, next year I\u2019ll look to automate this one step further.\nWe may also look at having a few slightly different layouts to choose from, so that each day isn\u2019t exactly the same as the last. Interestingly, we could even try some A/B tests to see if there\u2019s any particular format of image or type of quote that does a better job of grabbing attention. There are lots of possibilities!\n\nBy using a bit of ingenuity, some custom CMS templates, and the very useful Puppeteer project, we\u2019ve been able to reliably produce dynamic social media sharing images for all of our articles. In doing so, we reduced the dependancy on any individual for producing those images, and opened up a world of possibilities in how we use those images.\nI hope you\u2019ll give it a try!", "year": "2018", "author": "Drew McLellan", "author_slug": "drewmclellan", "published": "2018-12-24T00:00:00+00:00", "url": "https://24ways.org/2018/dynamic-social-sharing-images/", "topic": "code"}
{"rowid": 271, "title": "Creating Custom Font Stacks with Unicode-Range", "contents": "Any web designer or front-end developer worth their salt will be familiar with the CSS @font-face rule used for embedding fonts in a web page. We\u2019ve all used it \u2014 either directly in our code ourselves, or via one of the web font services like Fontdeck, Typekit or Google Fonts.\n\nIf you\u2019re like me, however, you\u2019ll be used to just copying and pasting in a specific incantation of lines designed to get different formats of fonts working in different browsers, and may not have really explored all the capabilities of @font-face properties as defined by the spec.\n\nOne such property \u2014 the unicode-range descriptor \u2014 sounds pretty dull and is easily overlooked. It does, however, have some fairly interesting possibilities when put to use in creative ways.\n\nUnicode-range\n\nThe unicode-range descriptor is designed to help when using fonts that don\u2019t have full coverage of the characters used in a page. By adding a unicode-range property to a @font-face rule it is possible to specify the range of characters the font covers. \n\n@font-face {\n    font-family: BBCBengali;\n    src: url(fonts/BBCBengali.ttf) format(\"opentype\");\n    unicode-range: U+00-FF;\n}\n\nIn this example, the font is to be used for characters in the range of U+00 to U+FF which runs from the unexciting control characters at the start of the Unicode table (symbols like the exclamation mark start at U+21) right through to \u00ff at U+FF \u2013 the extent of the Basic Latin character range.\n\nBy adding multiple @font-face rules for the same family but with different ranges, you can build up complete coverage of the characters your page uses by using different fonts.\n\nWhen I say that it\u2019s possible to specify the range of characters the font covers, that\u2019s true, but what you\u2019re really doing with the unicode-range property is declaring which characters the font should be used for. This becomes interesting, because instead of merely working with the technical constraints of available characters in a given font, we can start picking and choosing characters to use and selectively mix fonts together.\n\nThe best available ampersand\n\nA few years back, Dan Cederholm wrote a post encouraging designers to use the best available ampersand. Dan went on to outline how this can be achieved by wrapping our ampersands in a <span> element with a class applied:\n\n<span class=\"amp\">&</span>\n\nA CSS rule can then be written to select the <span> and apply a different font:\n\nspan.amp {\n    font-family: Baskerville, Palatino, \"Book Antiqua\", serif;\n}\n\nThat\u2019s a perfectly serviceable technique, but the drawbacks are clear \u2014 you have to add extra markup which is borderline presentational, and you also have to be able to add that markup, which isn\u2019t always possible when working with a CMS.\n\nPerhaps we could do this with unicode-range.\n\nA better best available ampersand\n\nThe Unicode code point for an ampersand is U+26, so the ampersand font stack above can be created like so:\n\n@font-face {\n    font-family: 'Ampersand';\n    src: local('Baskerville'), local('Palatino'), local('Book Antiqua');\n    unicode-range: U+26;\n}\n\nWhat we\u2019ve done here is specify a new family called Ampersand and created a font stack for it with the user\u2019s locally installed copies of Baskerville, Palatino or Book Antiqua. We\u2019ve then limited it to a single character range \u2014 the ampersand. Of course, those don\u2019t need to be local fonts \u2014 they could be web font files, too. If you have a font with a really snazzy ampersand, go for your life.\n\nWe can then use that new family in a regular font stack.\n\nh1 {\n    font-family: Ampersand, Arial, sans-serif;\n}\n\nWith this in place, any <h1> elements in our page will use the Ampersand family (Baskerville, Palatino or Book Antiqua) for ampersands, and Arial for all other characters. If the user doesn\u2019t have any of the Ampersand family fonts available, the ampersand will fall back to the next item in the font stack, Arial.\n\nYou didn\u2019t think it was that easy, did you?\n\nOh, if only it were so. The problem comes, as ever, with the issue of browser support. The unicode-range property has good support in WebKit browsers (like Safari and Chrome, and the browsers on most popular smartphone platforms) and in recent versions of Internet Explorer. The big stumbling block comes in the form of Firefox, which has no support at all.\n\nIf you\u2019re familiar with how CSS works when it comes to unsupported properties, you\u2019ll know that if a browser encounters a property it doesn\u2019t implement, it just skips that declaration and moves on to the next. That works perfectly for things like border-radius \u2014 if the browser can\u2019t round off the corners, the declaration is skipped and the user sees square corners instead. Perfect.\n\nLess perfect when it comes to unicode-range, because if no range is specified then the default is that the font is applied for all characters \u2014 the whole range. If you\u2019re using a fancy font for flamboyant ampersands, you probably don\u2019t want that applied to all your text if unicode-range isn\u2019t supported. That would be bad. Really bad.\n\nEnsuring good fallbacks\n\nAs ever, the trick is to make sure that there\u2019s a sensible fallback in place if a browser doesn\u2019t have support for whatever technology you\u2019re trying to use. This is where being a super nerd about understanding the spec you\u2019re working with really pays off.\n\nWe can make use of the rules of the CSS cascade to make sure that if unicode-range isn\u2019t supported we get a sensible fallback font. What would be ideal is if we were able to follow up the @font-face rule with a second rule to override it if Unicode ranges aren\u2019t implemented.\n\n@font-face {\n    font-family: 'Ampersand';\n    src: local('Baskerville'), local('Palatino'), local('Book Antiqua');\n    unicode-range: U+26;\n}\n@font-face {\n    font-family: 'Ampersand';\n    src: local('Arial');\n}\n\nIn theory, this code should make sense for all browsers. For those that support unicode-range the two rules become cumulative. They specify different ranges for the same family, and in WebKit browsers this has the expected result of using Arial for most characters, but Baskerville and friends for the ampersand. For browsers that don\u2019t have support, the second rule should just supersede the first, setting the font to Arial. \n\nUnfortunately, this code causes current versions of Firefox to freak out and use the first rule, applying Baskerville to the entire range. That\u2019s both unexpected and unfortunate. Bad Firefox. On your rug.\n\nIf that doesn\u2019t work, what can we do? Well, we know that if given a unicode-range Firefox will ignore the range and apply the font to all characters. That\u2019s really what we\u2019re trying to achieve. So what if we specified a range for the fallback font, but made sure it only covers some obscure high-value Unicode character we\u2019re never going to use in our page? Then it wouldn\u2019t affect the outcome for browsers that do support ranges.\n\n@font-face {\n    font-family: 'Ampersand';\n    src: local('Baskerville'), local('Palatino'), local('Book Antiqua');\n    unicode-range: U+26;\n}\n@font-face {\n    /* Ampersand fallback font */\n    font-family: 'Ampersand';\n    src: local('Arial');\n    unicode-range: U+270C;\n}\n\nBy specifying a range on the fallback font, Firefox appears to correctly override the first based on the cascade sort order. Browsers that do support ranges take the second rule in addition, and apply Arial for that obscure character we\u2019re not using in any of our pages \u2014 U+270C.\n\nSo we get our nice ampersands in browsers that support unicode-range and, thanks to our styling of an obscure Unicode character, the font falls back to a perfectly acceptable Arial in browsers that do not offer support. Perfect!\n\nThat obscure character, my friends, is what Unicode defines as the VICTORY HAND.\n\n\u270c\n\nSo, how can we use this?\n\nAmpersands are a neat trick, and it works well in browsers that support ranges, but that\u2019s not really the point of all this. Styling ampersands is fun, but they\u2019re only really scratching the surface. Consider more involved examples, such as substituting a different font for numerals, or symbols, or even caps. Things certainly begin to get a bit more interesting.\n\nHow do you know what the codes are for different characters? Richard Ishida has a handy online conversion tool available where you can type in the characters and get the Unicode code points out the other end.\n\nOf course, the fact remains that browser support for unicode-range is currently limited, so any application needs to have fallbacks that you\u2019re still happy for a significant proportion of your visitors to see. In some cases, such as dedicated pages for mobile devices in an HTML-based phone app, this is immediately useful as support in WebKit browsers is already very good. In other cases, you\u2019ll have to use your own best judgement based on your needs and audience.\n\nOne thing to keep in mind is that if you\u2019re using web fonts, the entire font will be downloaded even if only one character is used. That said, the font shouldn\u2019t be downloaded if none of the characters within the Unicode range are present in a given page.\n\nAs ever, there are pros and cons to using unicode-range as well as varied but increasing support in browsers. It remains a useful tool to understand and have in your toolkit for when the right moment comes along.", "year": "2011", "author": "Drew McLellan", "author_slug": "drewmclellan", "published": "2011-12-01T00:00:00+00:00", "url": "https://24ways.org/2011/creating-custom-font-stacks-with-unicode-range/", "topic": "code"}
{"rowid": 276, "title": "Your jQuery: Now With 67% Less Suck", "contents": "Fun fact: more websites are now using jQuery than Flash.\n\njQuery is an amazing tool that\u2019s made JavaScript accessible to developers and designers of all levels of experience. However, as Spiderman taught us, \u201cwith great power comes great responsibility.\u201d The unfortunate downside to jQuery is that while it makes it easy to write JavaScript, it makes it easy to write really really f*&#ing bad JavaScript. Scripts that slow down page load, unresponsive user interfaces, and spaghetti code knotted so deep that it should come with a bottle of whiskey for the next sucker developer that has to work on it. \n\nThis becomes more important for those of us who have yet to move into the magical fairy wonderland where none of our clients or users view our pages in Internet Explorer. The IE JavaScript engine moves at the speed of an advancing glacier compared to more modern browsers, so optimizing our code for performance takes on an even higher level of urgency.\n\nThankfully, there are a few very simple things anyone can add into their jQuery workflow that can clear up a lot of basic problems. When undertaking code reviews, three of the areas where I consistently see the biggest problems are: inefficient selectors; poor event delegation; and clunky DOM manipulation. We\u2019ll tackle all three of these and hopefully you\u2019ll walk away with some new jQuery batarangs to toss around in your next project.\n\nSelector optimization\n\nSelector speed: fast or slow?\n\nSaying that the power behind jQuery comes from its ability to select DOM elements and act on them is like saying that Photoshop is a really good tool for selecting pixels on screen and making them change color \u2013 it\u2019s a bit of a gross oversimplification, but the fact remains that jQuery gives us a ton of ways to choose which element or elements in a page we want to work with. However, a surprising number of web developers are unaware that all selectors are not created equal; in fact, it\u2019s incredible just how drastic the performance difference can be between two selectors that, at first glance, appear nearly identical. For instance, consider these two ways of selecting all paragraph tags inside a <div> with an ID.\n\n$(\"#id p\");\n\n$(\"#id\").find(\"p\");\n\nWould it surprise you to learn that the second way can be more than twice as fast as the first? Knowing which selectors outperform others (and why) is a pretty key building block in making sure your code runs well and doesn\u2019t frustrate your users waiting for things to happen.\n\nThere are many different ways to select elements using jQuery, but the most common ways can be basically broken down into five different methods. In order, roughly, from fastest to slowest, these are:\n\n\n\t$(\"#id\"); \nThis is without a doubt the fastest selector jQuery provides because it maps directly to the native document.getElementbyId() JavaScript method. If possible, the selectors listed below should be prefaced with an ID selector in conjunction with jQuery\u2019s .find() method to limit the scope of the page that has to be searched (as in the $(\"#id\").find(\"p\") example shown above).\n\t$(\"p\");, $(\"input\");, $(\"form\"); and so on\nSelecting elements by tag name is also fast, since it maps directly to the native document.getElementsByTagname() method.\n\t$(\".class\"); \nSelecting by class name is a little trickier. While still performing very well in modern browsers, it can cause some pretty significant slowdowns in IE8 and below. Why? IE9 was the first IE version to support the native document.getElementsByClassName() JavaScript method. Older browsers have to resort to using much slower DOM-scraping methods that can really impact performance.\n\t$(\"[attribute=value]\");\nThere is no native JavaScript method for this selector to use, so the only way that jQuery can perform the search is by crawling the entire DOM looking for matches. Modern browsers that support the querySelectorAll() method will perform better in certain cases (Opera, especially, runs these searches much faster than any other browser) but, generally speaking, this type of selector is Slowey McSlowersons.\n\t$(\":hidden\");\nLike attribute selectors, there is no native JavaScript method for this one to use. Pseudo-selectors can be painfully slow since the selector has to be run against every element in your search space. Again, modern browsers with querySelectorAll() will perform slightly better here, but try to avoid these if at all possible. If you must use one, try to limit the search space to a specific portion of the page: $(\"#list\").find(\":hidden\");\n\n\nBut, hey, proof is in the performance testing, right? It just so happens that said proof is sitting right here. Be sure to notice the class selector numbers beside IE7 and 8 compared to other browsers and then wonder how the people on the IE team at Microsoft manage to sleep at night. Yikes.\n\nChaining\n\nAlmost all jQuery methods return a jQuery object. This means that when a method is run, its results are returned and you can continue executing more methods on them. Rather than writing out the same selector multiple times over, just making a selection once allows multiple actions to be run on it.\n\nWithout chaining\n\n$(\"#object\").addClass(\"active\");\n$(\"#object\").css(\"color\",\"#f0f\");\n$(\"#object\").height(300);\n\nWith chaining\n\n$(\"#object\").addClass(\"active\").css(\"color\", \"#f0f\").height(300);\n\nThis has the dual effect of making your code shorter and faster. Chained methods will be slightly faster than multiple methods made on a cached selector, and both ways will be much faster than multiple methods made on non-cached selectors. Wait\u2026 \u201ccached selector\u201d? What is this new devilry? \n\nCaching\n\nAnother easy way to speed up your code that seems to be a mystery to developers is the idea of caching your selectors. Think of how many times you end up writing the same selector over and over again in any project. Every $(\".element\") selector has to search the entire DOM each time, regardless of whether or not that selector had been previously run. Running the selection once and then storing the results in a variable means that the DOM only has to be searched once. Once the results of a selector have been cached, you can do anything with them.\n\nFirst, run your search (here we\u2019re selecting all of the <li> elements inside <ul id=\"blocks\">): \n\nvar blocks = $(\"#blocks\").find(\"li\");\n\nNow, you can use the blocks variable wherever you want without having to search the DOM every time.\n\n$(\"#hideBlocks\").click(function() {\n    blocks.fadeOut();\n});\n$(\"#showBlocks\").click(function() {\n    blocks.fadeIn();\n});\n\nMy advice? Any selector that gets run more than once should be cached. This jsperf test shows just how much faster a cached selector runs compared to a non-cached one (and even throws some chaining love in to boot).\n\nEvent delegation\n\nEvent listeners cost memory. In complex websites and apps it\u2019s not uncommon to have a lot of event listeners floating around, and thankfully jQuery provides some really easy methods for handling event listeners efficiently through delegation.\n\nIn a bit of an extreme example, imagine a situation where a 10\u00d710 cell table needs to have an event listener on each cell; let\u2019s say that clicking on a cell adds or removes a class that defines the cell\u2019s background color. A typical way that this might be written (and something I\u2019ve often seen during code reviews) is like so:\n\n$('table').find('td').click(function() {\n    $(this).toggleClass('active');\n});\n\njQuery 1.7 has provided us with a new event listener method, .on(). It acts as a utility that wraps all of jQuery\u2019s previous event listeners into one convenient method, and the way you write it determines how it behaves. To rewrite the above .click() example using .on(), we\u2019d simply do the following:\n\n$('table').find('td').on('click',function() {\n    $(this).toggleClass('active');\n});\n\nSimple enough, right? Sure, but the problem here is that we\u2019re still binding one hundred event listeners to our page, one to each individual table cell. A far better way to do things is to create one event listener on the table itself that listens for events inside it. Since the majority of events bubble up the DOM tree, we can bind a single event listener to one element (in this case, the <table>) and wait for events to bubble up from its children. The way to do this using the .on() method requires only one change from our code above:\n\n$('table').on('click','td',function() {\n    $(this).toggleClass('active');\n});\n\nAll we\u2019ve done is moved the td selector to an argument inside the .on() method. Providing a selector to .on() switches it into delegation mode, and the event is only fired for descendants of the bound element (table) that match the selector (td). With that one simple change, we\u2019ve gone from having to bind one hundred event listeners to just one. You might think that the browser having to do one hundred times less work would be a good thing and you\u2019d be completely right. The difference between the two examples above is staggering.\n\n(Note that if your site is using a version of jQuery earlier than 1.7, you can accomplish the very same thing using the .delegate() method. The syntax of how you write the function differs slightly; if you\u2019ve never used it before, it\u2019s worth checking the API docs for that page to see how it works.)\n\nDOM manipulation\n\njQuery makes it very easy to manipulate the DOM. It\u2019s trivial to create new nodes, insert them, remove other ones, move things around, and so on. While the code to do this is simple to write, every time the DOM is manipulated, the browser has to repaint and reflow content which can be extremely costly. This is no more evident than in a long loop, whether it be a standard for() loop, while() loop, or jQuery $.each() loop.\n\nIn this case, let\u2019s say we\u2019ve just received an array full of image URLs from a database or Ajax call or wherever, and we want to put all of those images in an unordered list. Commonly, you\u2019ll see code like this to pull this off:\n\nvar arr = [reallyLongArrayOfImageURLs]; \n    $.each(arr, function(count, item) {\n        var newImg = '<li><img src=\"'+item+'\"></li>';\n        $('#imgList').append(newImg);\n    });\n\nThere are a couple of problems with this. For one (which you should have already noticed if you\u2019ve read the earlier part of this article), we\u2019re making the $(\"#imgList\") selection once for each iteration of our loop. The other problem here is that each time the loop iterates, it\u2019s adding a new <li> to the DOM. Each of those insertions is going to be costly, and if our array is quite large then this could lead to a massive slowdown or even the dreaded \u2018A script is causing this page to run slowly\u2019 warning.\n\nvar arr = [reallyLongArrayOfImageURLs],\n    tmp = ''; \n$.each(arr, function(count, item) {\n    tmp += '<li><img src=\"'+item+'\"></li>';\n});\n$('#imgList').append(tmp);\n\nAll we\u2019ve done here is create a tmp variable that each <li> is added to as it\u2019s created. Once our loop has finished iterating, that tmp variable will contain all of our list items in memory, and can be appended to our <ul> all in one go. Browsers work much faster when working with objects in memory rather than on screen, so this is a much faster, more CPU-cycle-friendly method of building a list.\n\nWrapping up\n\nThese are far from being the only ways to make your jQuery code run better, but they are among the simplest ones to implement. Though each individual change may only make a few milliseconds of difference, it doesn\u2019t take long for those milliseconds to add up. Studies have shown that the human eye can discern delays of as few as 100ms, so simply making a few changes sprinkled throughout your code can very easily have a noticeable effect on how well your website or app performs. Do you have other jQuery optimization tips to share? Leave them in the comments and help make us all better.\n\nNow go forth and make awesome!", "year": "2011", "author": "Scott Kosman", "author_slug": "scottkosman", "published": "2011-12-13T00:00:00+00:00", "url": "https://24ways.org/2011/your-jquery-now-with-less-suck/", "topic": "code"}
{"rowid": 283, "title": "CSS3 Patterns, Explained", "contents": "Many of you have probably seen my CSS3 patterns gallery. It became very popular throughout the year and it showed many web developers how powerful CSS3 gradients really are. But how many really understand how these patterns are created? The biggest benefit of CSS-generated backgrounds is that they can be modified directly within the style sheet. This benefit is void if we are just copying and pasting CSS code we don\u2019t understand. We may as well use a data URI instead.\n\nImportant note\n\nIn all the examples that follow, I\u2019ll be using gradients without a vendor prefix, for readability and brevity. However, you should keep in mind that in reality you need to use all the vendor prefixes (-moz-, -ms-, -o-, -webkit-) as no browser currently implements them without a prefix. Alternatively, you could use -prefix-free and have the current vendor prefix prepended at runtime, only when needed.\n\nThe syntax described here is the one that browsers currently implement. The specification has since changed, but no browser implements the changes yet. If you are interested in what is coming, I suggest you take a look at the dev version of the spec.\n\nIf you are not yet familiar with CSS gradients, you can read these excellent tutorials by John Allsopp and return here later, as in the rest of the article I assume you already know the CSS gradient basics:\n\n\n\tCSS3 Linear Gradients\n\tCSS3 Radial Gradients\n\n\nThe main idea\n\nI\u2019m sure most of you can imagine the background this code generates:\n\nbackground: linear-gradient(left, white 20%, #8b0 80%);\n\nIt\u2019s a simple gradient from one color to another that looks like this:\n\n See this example live\n\nAs you probably know, in this case the first 20% of the container\u2019s width is solid white and the last 20% is solid green. The other 60% is a smooth gradient between these colors. Let\u2019s try moving these color stops closer to each other:\n\nbackground: linear-gradient(left, white 30%, #8b0 70%);\n\n See this example live\n\nbackground: linear-gradient(left, white 40%, #8b0 60%);\n\n See this example live\n\nbackground: linear-gradient(left, white 50%, #8b0 50%);\n\n See this example live\n\nNotice how the gradient keeps shrinking and the solid color areas expanding, until there is no gradient any more in the last example. We can even adjust the position of these two color stops to control where each color abruptly changes into another:\n\nbackground: linear-gradient(left, white 30%, #8b0 30%);\n\n See this example live\n\nbackground: linear-gradient(left, white 90%, #8b0 90%);\n\n See this example live\n\nWhat you need to take away from these examples is that when two color stops are at the same position, there is no gradient, only solid colors. Even without going any further, this trick is useful for a number of different use cases like faux columns or the effect I wanted to achieve in my homepage or the -prefix-free page where the background is only shown on one side and hidden on the other:\n\n\n\nCombining with background-size\n\nWe can do wonders, however, if we combine this with the CSS3 background-size property:\n\nbackground: linear-gradient(left, white 50%, #8b0 50%);\nbackground-size: 100px 100px;\n\n See this example live\n\nAnd there it is. We just created the simplest of patterns: (vertical) stripes. We can remove the first parameter (left) or replace it with top and we\u2019ll get horizontal stripes. However, let\u2019s face it: Horizontal and vertical stripes are kinda boring. Most stripey backgrounds we see on the web are diagonal. So, let\u2019s try doing that.\n\nOur first attempt would be to change the angle of the gradient to something like 45deg. However, this results in an ugly pattern like this: \n\n See this example live\n\nBefore reading on, think for a second: why didn\u2019t this produce the desired result? Can you figure it out?\n\nThe reason is that the gradient angle rotates the gradient inside each tile, not the tiled background as a whole. However, didn\u2019t we have the same problem the first time we tried to create diagonal stripes with an image? And then we learned that every stripe has to be included twice, like so:\n\n\n\nSo, let\u2019s try to create that effect with CSS gradients. It\u2019s essentially what we tried before, but with more color stops:\n\nbackground: linear-gradient(45deg, white 25%,\n    #8b0 25%, #8b0 50%, \n    white 50%, white 75%, \n    #8b0 75%);\nbackground-size:100px 100px;\n\n See this example live\n\nAnd there we have our stripes! An easy way to remember the order of the percentages and colors it is that you always have two of the same in succession, except the first and last color.\n\nNote: Firefox for Mac also needs an additional 100% color stop at the end of any pattern with more than two stops, like so: ..., white 75%, #8b0 75%, #8b0). The bug was reported in February 2011 and you can vote for it and track its progress at Bugzilla.\n\nUnfortunately, this is essentially a hack and we will realize that if we try to change the gradient angle to 60deg:\n\n See this example live\n\nNot that maintainable after all, eh? Luckily, CSS3 offers us another way of declaring such backgrounds, which not only helps this case but also results in much more concise code:\n\nbackground: repeating-linear-gradient(60deg, white, white 35px, #8b0 35px, #8b0 70px);\n\n See this example live\n\nIn this case, however, the size has to be declared in the color stop positions and not through background-size, since the gradient is supposed to cover the entire container. You might notice that the declared size is different from the one specified the previous way. This is because the size of the stripes is measured differently: in the first example we specify the dimensions of the tile itself; in the second, the width of the stripes (35px), which is measured diagonally.\n\nMultiple backgrounds\n\nUsing only one gradient you can create stripes and that\u2019s about it. There are a few more patterns you can create with just one gradient (linear or radial) but they are more or less boring and ugly. Almost every pattern in my gallery contains a number of different backgrounds. For example, let\u2019s create a polka dot pattern:\n\nbackground: radial-gradient(circle, white 10%, transparent 10%),\nradial-gradient(circle, white 10%, black 10%) 50px 50px;\nbackground-size:100px 100px;\n\n See this example live\n\nNotice that the two gradients are almost the same image, but positioned differently to create the polka dot effect. The only difference between them is that the first (topmost) gradient has transparent instead of black. If it didn\u2019t have transparent regions, it would effectively be the same as having a single gradient, as the topmost gradient would obscure everything beneath it.\n\nThere is an issue with this background. Can you spot it?\n\nThis background will be fine for browsers that support CSS gradients but, for browsers that don\u2019t, it will be transparent as the whole declaration is ignored. We have two ways to provide a fallback, each for different use cases. We have to either declare another background before the gradient, like so:\n\nbackground: black;\nbackground: radial-gradient(circle, white 10%, transparent 10%),\nradial-gradient(circle, white 10%, black 10%) 50px 50px;\nbackground-size:100px 100px;\n\nor declare each background property separately:\n\nbackground-color: black;\nbackground-image: radial-gradient(circle, white 10%, transparent 10%),\nradial-gradient(circle, white 10%, transparent 10%);\nbackground-size:100px 100px;\nbackground-position: 0 0, 50px 50px;\n\nThe vigilant among you will have noticed another change we made to our code in the last example: we altered the second gradient to have transparent regions as well. This way background-color serves a dual purpose: it sets both the fallback color and the background color of the polka dot pattern, so that we can change it with just one edit. Always strive to make code that can be modified with the least number of edits. You might think that it will never be changed in that way but, almost always, given enough time, you\u2019ll be proved wrong.\n\nWe can apply the exact same technique with linear gradients, in order to create checkerboard patterns out of right triangles:\n\nbackground-color: white;\nbackground-image: linear-gradient(45deg, black 25%, transparent 25%, transparent 75%, black 75%), \nlinear-gradient(45deg, black 25%, transparent 25%, transparent 75%, black 75%);\nbackground-size:100px 100px;\nbackground-position: 0 0, 50px 50px;\n\n See this example live\n\nUsing the right units\n\nDon\u2019t use pixels for the sizes without any thought. In some cases, ems make much more sense. For example, when you want to make a lined paper background, you want the lines to actually follow the text. If you use pixels, you have to change the size every time you change font-size. If you set the background-size in ems, it will naturally follow the text and you will only have to update it if you change line-height.\n\nIs it possible?\n\nThe shapes that can be achieved with only one gradient are:\n\n\n\tstripes\n\tright triangles\n\tcircles and ellipses\n\tsemicircles and other shapes formed from slicing ellipses horizontally or vertically\n\n\nYou can combine several of them to create squares and rectangles (two right triangles put together), rhombi and other parallelograms (four right triangles), curves formed from parts of ellipses, and other shapes.\n\nJust because you can doesn\u2019t mean you should\n\nTechnically, anything can be crafted with these techniques. However, not every pattern is suitable for it. The main advantages of this technique are:\n\n\n\tno extra HTTP requests\n\tshort code\n\thuman-readable code (unlike data URIs) that can be changed without even leaving the CSS file.\n\n\nComplex patterns that require a large number of gradients are probably better left to SVG or bitmap images, since they negate almost every advantage of this technique:\n\n\n\tthey are not shorter\n\tthey are not really comprehensible \u2013 changing them requires much more effort than using an image editor\n\n\nThey still save an HTTP request, but so does a data URI.\n\nI have included some very complex patterns in my gallery, because even though I think they shouldn\u2019t be used in production (except under very exceptional conditions), understanding how they work and coding them helps somebody understand the technology in much more depth.\n\nAnother rule of thumb is that if your pattern needs shapes to obscure parts of other shapes, like in the star pattern or the yin yang pattern, then you probably shouldn\u2019t use it. In these patterns, changing the background color requires you to also change the color of these shapes, making edits very tedious.\n\nIf a certain pattern is not practicable with a reasonable amount of CSS, that doesn\u2019t mean you should resort to bitmap images. SVG is a very good alternative and is supported by all modern browsers.\n\nBrowser support\n\nCSS gradients are supported by Firefox 3.6+, Chrome 10+, Safari 5.1+ and Opera 11.60+ (linear gradients since Opera 11.10). Support is also coming in Internet Explorer when IE10 is released. You can get gradients in older WebKit versions (including most mobile browsers) by using the proprietary -webkit-gradient(), if you really need them.\n\nEpilogue\n\nI hope you find these techniques useful for your own designs. If you come up with a pattern that\u2019s very different from the ones already included, especially if it demonstrates a cool new technique, feel free to send a pull request to the github repo of the patterns gallery. Also, I\u2019m always fascinated to see my techniques put in practice, so if you made something cool and used CSS patterns, I\u2019d love to know about it!\n\nHappy holidays!", "year": "2011", "author": "Lea Verou", "author_slug": "leaverou", "published": "2011-12-16T00:00:00+00:00", "url": "https://24ways.org/2011/css3-patterns-explained/", "topic": "code"}
{"rowid": 288, "title": "Displaying Icons with Fonts and Data- Attributes", "contents": "Traditionally, bitmap formats such as PNG have been the standard way of delivering iconography on websites. They\u2019re quick and easy, and it also ensures they\u2019re as pixel crisp as possible. Bitmaps have two drawbacks, however: multiple HTTP requests, affecting the page\u2019s loading performance; and a lack of scalability, noticeable when the page is zoomed or viewed on a screen with a high pixel density, such as the iPhone 4 and 4S.\n\nThe requests problem is normally solved by using CSS sprites, combining the icon set into one (physically) large image file and showing the relevant portion via background-position. While this works well, it can get a bit fiddly to specify all the positions. In particular, scalability is still an issue. A vector-based format such as SVG sounds ideal to solve this, but browser support is still patchy.\n\n\n\nThe rise and adoption of web fonts have given us another alternative. By their very nature, they\u2019re not only scalable, but resolution-independent too. No need to specify higher resolution graphics for high resolution screens! \n\nThat\u2019s not all though:\n\n\n\tBrowser support: Unlike a lot of new shiny techniques, they have been supported by Internet Explorer since version 4, and, of course, by all modern browsers. We do need several different formats, however!\n\tDesign on the fly: The font contains the basic graphic, which can then be coloured easily with CSS \u2013 changing colours for themes or :hover and :focus styles is done with one line of CSS, rather than requiring a new graphic. You can also use CSS3 properties such as text-shadow to add further effects. Using -webkit-background-clip: text;, it\u2019s possible to use gradient and inset shadow effects, although this creates a bitmap mask which spoils the scalability.\n\tSmall file size: specially designed icon fonts, such as Drew Wilson\u2019s Pictos font, can be as little as 12Kb for the .woff font. This is because they contain fewer characters than a fully fledged font. You can see Pictos being used in the wild on sites like Garrett Murray\u2019s Maniacal Rage.\n\n\nAs with all formats though, it\u2019s not without its disadvantages: \n\n\n\tIcons can only be rendered in monochrome or with a gradient fill in browsers that are capable of rendering CSS3 gradients. Specific parts of the icon can\u2019t be a different colour.\n\tIt\u2019s only appropriate when there is an accompanying text to provide meaning. This can be alleviated by wrapping the text label in a tag (I like to use <b> rather than <span>, due to the fact that it\u2019s smaller and isn\u2019 t being used elsewhere) and then hiding it from view with text-indent:-999em.\n\tCreating an icon font can be a complex and time-consuming process. While font editors can carry out hinting automatically, the best results are achieved manually.\n\tUnless you\u2019re adept at creating your own fonts, you\u2019re restricted to what is available in the font. However, fonts like Pictos will cover the most common needs, and icons are most effective when they\u2019re using familiar conventions.\n\n\nThe main complaint about using fonts for icons is that it can mean adding a meaningless character to our markup. The good news is that we can overcome this by using one of two methods \u2013 CSS generated content or the data-icon attribute \u2013 in combination with the :before and :after pseudo-selectors, to keep our markup minimal and meaningful. \n\nOur simple markup looks like this:\n\n<a href=\"/basket\" class=\"icon basket\">View Basket</a>\n\nNote the multiple class attributes. Next, we\u2019ll import the Pictos font using the @font-face web fonts property in CSS:\n\n@font-face {\n    font-family: 'Pictos';\n    src: url('pictos-web.eot');\n    src: local('\u263a'), \n    url('pictos-web.woff') format('woff'), \n    url('pictos-web.ttf') format('truetype'),\n    url('pictos-web.svg#webfontIyfZbseF') format('svg');\n}\n\nThis rather complicated looking set of rules is (at the time of writing) the most bulletproof way of ensuring as many browsers as possible load the font we want.  We\u2019ll now use the content property applied to the :before pseudo-class selector to generate our icon. Once again, we\u2019ll use those multiple class attribute values to set common icon styles, then specific styles for .basket. This helps us avoid repeating styles:\n\n.icon {\n    font-family: 'Pictos';\n    font-size: 22px:\n}\n\n.basket:before {\n    content: \"$\";\n}\n\nWhat does the :before pseudo-class do? It generates the dollar character in a browser, even when it\u2019s not present in the markup. Using the generated content approach means our markup stays simple, but we\u2019ll need a new line of CSS, defining what letter to apply to each class attribute for every icon we add.\n\ndata-icon is a new alternative approach that uses the HTML5 data- attribute in combination with CSS attribute selectors. This new attribute lets us add our own metadata to elements, as long as its prefixed by data- and doesn\u2019t contain any uppercase letters. In this case, we want to use it to provide the letter value for the icon. Look closely at this markup and you\u2019ll see the data-icon attribute.\n\n<a href=\"/basket\" class=\"icon\" data-icon=\"$\">View Basket</a>\n\n\n\nWe could add others, in fact as many as we like.\n\n<a href=\"/\" class=\"icon\" data-icon=\"k\">Favourites</a>\n<a href=\"/\" class=\"icon\" data-icon=\"t\">History</a>\n<a href=\"/\" class=\"icon\" data-icon=\"@\">Location</a>\n\n\n\nThen, we need just one CSS attribute selector to style all our icons in one go:\n\n.icon:before {\n    content: attr(data-icon);\n    /* Insert your fancy colours here */\n    }\n\nBy placing our custom attribute data-icon in the selector in this way, we can enable CSS to read the value of that attribute and display it before the element (in this case, the anchor tag). It saves writing a lot of CSS rules. I can imagine that some may not like the extra attribute, but it does keep it out of the actual content \u2013 generated or not.\n\n\n\n\n\nThis could be used for all manner of tasks, including a media player and large simple illustrations. See the demo for live examples. Go ahead and zoom the page, and the icons will be crisp, with the exception of the examples that use -webkit-background-clip: text as mentioned earlier.\n\nFinally, it\u2019s worth pointing out that with both generated content and the data-icon method, the letter will be announced to people using screen readers. For example, with the shopping basket icon above, the reader will say \u201cdollar sign view basket\u201d. As accessibility issues go, it\u2019s not exactly the worst, but could be confusing. You would need to decide whether this method is appropriate for the audience. Despite the disadvantages, icon fonts have huge potential.", "year": "2011", "author": "Jon Hicks", "author_slug": "jonhicks", "published": "2011-12-12T00:00:00+00:00", "url": "https://24ways.org/2011/displaying-icons-with-fonts-and-data-attributes/", "topic": "code"}
{"rowid": 289, "title": "Front-End Developers Are Information Architects Too", "contents": "The theme of this year\u2019s World IA Day was \u201cInformation Everywhere, Architects Everywhere\u201d. This article isn\u2019t about what you may consider an information architect to be: someone in the user-experience field, who maybe studied library science, and who talks about taxonomies. This is about a realisation I had a couple of years ago when I started to run an increasing amount of usability-testing sessions with people who have disabilities: that the structure, labelling, and connections that can be made in front-end code is information architecture. People\u2019s ability to be successful online is unequivocally connected to the quality of the code that is written.\nPlaces made of information\nIn information architecture we talk about creating places made of information. These places are made of ones and zeros, but we talk about them as physical structures. We talk about going onto a social media platform, posting in blogs, getting locked out of an environment, and building applications. In 2002, Andrew Hinton stated:\n\nPeople live and work in these structures, just as they live and work in their homes, offices, factories and malls. These places are not virtual: they are as real as our own minds.\n25 Theses\n\nWe\u2019re creating structures which people rely on for significant parts of their lives, so it\u2019s critical that we carry out our work responsibly. This means we must use our construction materials correctly. Luckily, our most important material, HTML, has a well-documented specification which tells us how to build robust and accessible places. What is most important, I believe, is to understand the semantics of HTML.\nSemantics\nThe word \u201csemantic\u201d has its origin in Greek words meaning \u201csignificant\u201d, \u201csignify\u201d, and \u201csign\u201d. In the physical world, a structure can have semantic qualities that tell us something about it. For example, the stunning Westminster Abbey inspires awe and signifies much about the intent and purpose of the structure. The building\u2019s size; the quality of the stone work; the massive, detailed stained glass: these are all signs that this is a building meant for something the creators deemed important. Alternatively consider a set of large, clean, well-positioned, well-lit doors on the ground floor of an office block: they don\u2019t need an \u201centrance\u201d sign to communicate their use and to stop people trying to use a nearby fire exit to get into the building. The design of the doors signify their usage. Sometimes a more literal and less awe-inspiring approach to communicating a building\u2019s purpose happens, but the affect is similar: the building is signifying something about its purpose.\nHTML has over 115 elements, many of which have semantics to signify structure and affordance to people, browsers, and assistive technology. The HTML 5.1 specification mentions semantics, stating:\n\nElements, attributes, and attribute values in HTML are defined \u2026 to have certain meanings (semantics). For example, the <ol> element represents an ordered list, and the lang attribute represents the language of the content.\nHTML 5.1 Semantics, structure, and APIs of HTML documents\n\nHTML\u2019s baked-in semantics means that developers can architect their code to signify structure, create relationships between elements, and label content so people can understand what they\u2019re interacting with. Structuring and labelling information to make it available, usable, and understandable to people is what an information architect does. It\u2019s also what a front-end developer does, whether they realise it or not.\nA brief introduction to information architecture\nWe\u2019re going to start by looking at what an information architect is. There are many definitions, and I\u2019m going to quote Richard Saul Wurman, who is widely regarded as the father of information architecture. In 1976 he said an information architect is:\n\nthe individual who organizes the patterns inherent in data, making the complex clear; a person who creates the structure or map of information which allows others to find their personal paths to knowledge; the emerging 21st century professional occupation addressing the needs of the age focused upon clarity, human understanding, and the science of the organization of information.\nOf Patterns And Structures\n\nTo me, this clearly defines any developer who creates code that a browser, or other user agent (for example, a screen reader), uses to create a structured, navigable place for people.\nJust as there are many definitions of what an information architect is, there are for information architecture itself. I\u2019m going to use the definition from the fourth edition of Information Architecture For The World Wide Web, in which the authors define it as:\nThe structural design of shared information environments.\nThe synthesis of organization, labeling, search, and navigation systems within digital, physical, and cross-channel ecosystems.\nThe art and science of shaping information products and experiences to support usability, findability, and understanding.\nInformation Architecture For The World Wide Web, 4th Edition\nTo me, this describes front-end development. Done properly, there is an art to creating robust, accessible, usable, and findable spaces that delight all our users. For example, at 2015\u2019s State Of The Browser conference, Edd Sowden talked about the accessibility of <table>s. He discovered that by simply not using the semantically-correct <th> element to mark up <table> headings, in some situations browsers will decide that a <table> is being used for layout and essentially make it invisible to assistive technology. Another example of how coding practices can affect the usability and findability of content is shown by L\u00e9onie Watson in her How ARIA landmark roles help screen reader users video. By using ARIA landmark roles, people who use screen readers are quickly able to identify and jump to common parts of a web page.\nOur definitions of information architects and information architecture mention patterns, rules, organisation, labelling, structure, and relationships. There are numerous different models for how these elements get boiled down to their fundamentals. In his Understanding Context book, Andrew Hinton calls them Labels, Relationships, and Rules; Jorge Arango calls them Links, Nodes, And Order; and Dan Klyn uses Ontology, Taxonomy, and Choreography, which is the one we\u2019re going to use. Dan defines these terms as:\nOntology\nThe definition and articulation of the rules and patterns that govern the meaning of what we intend to communicate.\nWhat we mean when we say what we say.\nTaxonomy\nThe arrangements of the parts. Developing systems and structures for what everything\u2019s called, where everything\u2019s sorted, and the relationships between labels and categories\nChoreography\nRules for interaction among the parts. The structures it creates foster specific types of movement and interaction; anticipating the way users and information want to flow and making affordance for change over time.\n\nWe now have definitions of an information architect, information architecture, and a model of the elements of information architecture. But is writing HTML really creating information or is it just wrangling data and metadata? When does data turn into information? In his book Managing For The Future Peter Drucker states:\n\n\u2026 data is not information. Information is data endowed with relevance and purpose.\nManaging For The Future\n\nIf we use the correct semantic element to mark up content then we\u2019re developing with purpose and creating relevance. For example, if we follow the advice of the HTML 5.1 specification and mark up headings using heading rank instead of the outline algorithm, we\u2019re creating a structure where the depth of one heading is relevant to the previous one. Architected correctly, an <h2> element should be relevant to its parent, which should be the <h1>. By following the HTML specification we can create a structured, searchable, labeled document that will hopefully be relevant to what our users need to be successful. If you\u2019ve never used a screen reader, you might be wondering how the headings on a page are searchable. Screen readers give users the ability to interact with headings in a couple of ways:\n\nby creating a list of headings so users can quickly scan the page for information\nby using a keyboard command to cycle through one heading at a time\n\nIf we had a document for Christmas Day TV we might structure it something like this:\n<h1>Christmas Day TV schedule</h1>\n  <h2>BBC1</h2>\n    <h3>Morning</h3>\n      <h3>Evening</h3>\n  <h2>BBC2</h2>\n    <h3>Morning</h3>\n    <h3>Evening</h3>\n  <h2>ITV</h2>\n    <h3>Morning</h3>\n    <h3>Evening</h3>\n  <h2>Channel 4</h2>\n    <h3>Morning</h3>\n    <h3>Evening</h3>\nIf I use VoiceOver to generate a list of headings, I get this:\n\nOnce I have that list I can use keyboard commands to filter the list based on the heading level. For example, I can press 2 to hear just the <h2>s:\n\nIf we hadn\u2019t used headings, of if we\u2019d nested them incorrectly, our users would be frustrated.\nPutting this together\nLet\u2019s put this together with an example of a button that, when pressed, toggles the appearance of a panel of links. There are numerous ways we could create a button on a web page, but the best way is to just use a <button>. Every browser understands what a <button> is, how it works, and what keyboard shortcuts should be used with them. The HTML specification for the <button> element says:\n\nThe <button> element represents a button labeled by its contents.\n\nThe contents that a <button> can have include the type attribute, any relevant ARIA attributes, and the actual text label that the user sees. This information is more important than the visual design: it doesn\u2019t matter how beautiful or obtuse the design is, if the underlying code is non-semantic and poorly labelled, people are going to struggle to use it. Here are three buttons, each created with the same HTML but with different designs:\n\nRegardless of what they look like, because we\u2019ve used semantic HTML instead of a bunch of meaningless <div>s or <span>s, people who use assistive technology are going to benefit. Out of the box, without any extra development effort, a <button> is accessible and usable with a keyboard. We don\u2019t have to write event handlers to listen for people pressing the Enter key or the space bar, which we would have to do if we\u2019d faked a button with non-semantic elements. Our <button> can also be quickly findable: for example, in the same way it\u2019s possible to create a list of headings with a screen reader, I can also create a list of form elements and then quickly jump to the one I want.\nNow we have our <button>, let\u2019s add the panel we\u2019re toggling the appearance of. Here\u2019s our code:\n<button aria-controls=\"panel\" aria-expanded=\"false\" class=\"settings\" id=\"settings\" type=\"button\">Settings</button>\n\n<div class=\"panel hidden\" id=\"panel\">\n    <ul aria-labelledby=\"settings\">\n        <li><a href=\"\u2026\">Account</a></li>\n        <li><a href=\"\u2026\">Privacy</a></li>\n        <li><a href=\"\u2026\">Security</a></li>\n    </ul>\n</div>\nThere\u2019s quite a bit going on here. We\u2019re using the:\n\naria-controls attribute to architect a connection between the <button> element and the panel whose appearance it controls. When some assistive technology, for example the JAWS screen reader, encounters an element with aria-controls it audibly tells a user about the controlled expanded element and gives them the ability to move focus to it.\naria-expanded attribute to denote whether the panel is visible or not. We toggle this value using JavaScript to true when the panel is visible and false when it\u2019s not. This important attribute tells people who use screen readers about the state of the elements they\u2019re interacting with. For example, VoiceOver announces Settings expanded button when the panel is visible and Settings collapsed button when it\u2019s hidden.\naria-labelledby attribute to give the list a title of \u201cSettings\u201d. This can benefit some users of assistive technology. For example, screen readers can cycle through all the lists on a page, so being able to title them can improve findability. Being able to hear list Settings three items is, I\u2019d argue, more useful than list three items. By doing this we\u2019re supporting usability and findability.\n<ul> element to contain our list of links in our panel.\n\nLet\u2019s look at the choice of <ul> to contain our settings choices. Firstly, our settings are related items, so they belong in a structure that semantically groups things. This is something that a list can do that other elements or patterns can\u2019t. This pattern, for example, isn\u2019t semantic and has no structure:\n<div><a href=\"\u2026\">Account</a></div>\n<div><a href=\"\u2026\">Privacy</a></div>\n<div><a href=\"\u2026\">Security</a></div>\nAll we have there is three elements next to each other on the screen and in the DOM. That is not robust code that signifies anything.\nWhy are we using an unordered list as opposed to an ordered list or a definition list? A quick look at the HTML specification tells us why:\n\nThe <ul> element represents a list of items, where the order of the items is not important \u2014 that is, where changing the order would not materially change the meaning of the document.\nThe HTML 5.1 specification\u2019s description of the  element\n\nWill the meaning of our document materially change if we moved the order of our links around? Nope. Therefore, I\u2019d argue, we\u2019ve used the correct element to structure our content.\nThese coding decisions are information architecture\nI believe that what we\u2019ve done here is pure information architecture. Going back to Dan Klyn\u2019s model, we\u2019ve practiced ontology by looking at the meaning of what we\u2019re intending to communicate:\n\nwe want to communicate there is an interactive element that toggles the appearance of an element on a page so we\u2019ve used one, a <button>, with those semantics.\nprogrammatically we\u2019ve used the type='button' attribute to signify that the button isn\u2019t a menu, reset, or submit element.\nvisually we\u2019ve designed our <button> look like something that can be interacted with and, importantly, we haven\u2019t removed the focus ring.\nwe\u2019ve labelled the <button> with the word \u201cSettings\u201d so that our users will hopefully understand what the button is for.\nwe\u2019ve used an <ul> element to structure and communicate our list of related items.\n\nWe\u2019ve also practiced taxonomy by developing systems and structures and creating relationships between our elements:\n\nby connecting the <button> to the panel using the aria-controls attribute we\u2019ve programmatically created a relationship between two elements.\nwe\u2019ve developed a structure in our elements by labelling our <ul> with the same name as the <button> that controls its appearance.\n\nAnd finally we\u2019ve practiced choreography by creating elements that foster movement and interaction. We\u2019ve anticipated the way users and information want to flow:\n\nwe\u2019ve used a <button> element that is interactive and accessible out of the box.\nour aria-controls attribute can help some people who use screen readers move easily from the <button> to the panel it controls.\nby toggling the value of the aria-expanded attribute we\u2019ve developed a system that tells assistive technology about the status of the relationship between our elements: the panel is visible or the panel is hidden.\nwe\u2019ve made sure our information is more usable and findable no matter how our users want or need to interact with it. Regardless of how someone \u201csees\u201d our work they\u2019re going to be able to use it because we\u2019ve architected multiple ways to access our information.\n\nInformation architecture, robust code, and accessibility\nThe United Nations estimates that around 10% of the world\u2019s population has some form of disability which, at the time of writing, is around 740,000,000 people. That\u2019s a lot of people who rely on well-architected semantic code that can be interpreted by whatever assistive technology they may need to use.\nIf everyone involved in the creation of our places made of information practiced information architecture it would make satisfying the WCAG 2.0 POUR principles so much easier. Our digital construction practices directly affect the quality of life of millions of people, and we have a responsibility to make technology available to them. In her book How To Make Sense Of Any Mess, Abby Covert states:\nIf we\u2019re going to be successful in this new world, we need to see information as a workable material and learn to architect it in a way that gets us to our goals.\nHow To Make Sense Of Any Mess\nI believe that the world will be a better place if we start treating front-end development as information architecture.", "year": "2016", "author": "Francis Storr", "author_slug": "francisstorr", "published": "2016-12-17T00:00:00+00:00", "url": "https://24ways.org/2016/front-end-developers-are-information-architects-too/", "topic": "code"}
{"rowid": 292, "title": "Watch Your Language!", "contents": "I\u2019m bilingual. My first language is French. I learned English in my early 20s. Learning a new language later in life meant that I was able to observe my thought processes changing over time. It made me realize that some concepts can\u2019t be expressed in some languages, while other languages express these concepts with ease.\nIt also helped me understand the way we label languages. English: business. French: romance. Here\u2019s an example of how words, or the absence thereof, can affect the way we think:\nIn French we love everything. There\u2019s no straightforward way to say we like something, so we just end up loving everything. I love my sisters, I love broccoli, I love programming, I love my partner, I love doing laundry (this is a lie), I love my mom (this is not a lie). I love, I love, I love. It\u2019s no wonder French is considered romantic. When I first learned English I used the word love rather than like because I hadn\u2019t grasped the difference. Needless to say, I\u2019ve scared away plenty of first dates!\nLearning another language made me realize the limitations of my native language and revealed concepts I didn\u2019t know existed. Without the nuances a given language provides, we fail to express what we really think. The absence of words in our vocabulary gets in the way of effectively communicating and considering ideas.\nWhen I lived in Montr\u00e9al, most people in my circle spoke both French and English. I could switch between them when I could more easily express an idea in one language or the other. I liked (or should I say loved?) those conversations. They were meaningful. They were efficient.\n\nI\u2019m quadrilingual. I code in Ruby, HTML/CSS, JavaScript, Python. In the past couple of years I have been lucky enough to write code in these languages at a massive scale. In learning Ruby, much like learning English, I discovered the strengths and limitations of not only the languages I knew but the language I was learning. It taught me to choose the right tool for the job.\nWhen I started working at Shopify, making a change to a view involved copy/pasting HTML and ERB from one view to another. The CSS was roughly structured into modules, but those modules were not responsive to different screen sizes. Our HTML was complete mayhem, and we didn\u2019t consider accessibility. All this made editing views a laborious process.\nGrep. Replace all. Test. Ship it. Repeat.\nThis wasn\u2019t sustainable at Shopify\u2019s scale, so the newly-formed front end team was given two missions:\n\nMake the app responsive (AKA Let\u2019s Make This Thing Responsive ASAP)\nMake the view layer scalable and maintainable (AKA Let\u2019s Build a Pattern Library\u2026 in Ruby)\n\nLet\u2019s make this thing responsive ASAP\nThe year was 2015. The Shopify admin wasn\u2019t mobile friendly. Our browser support was set to IE10. We had the wind in our sails. We wanted to achieve complete responsiveness in the shortest amount of time. Our answer: container queries.\nIt seemed like the obvious decision at the time. We would be able to set rules for each component in isolation and the component would know how to lay itself out on the page regardless of where it was rendered. It would save us a ton of development time since we wouldn\u2019t need to change our markup, it would scale well, and we would achieve complete component autonomy by not having to worry about page layout. By siloing our components, we were going to unlock the ultimate goal of componentization, cutting the tie to external dependencies. We were cool.\nWriting the JavaScript handling container queries was my first contribution to Shopify. It was a satisfying project to work on. We could drop our components in anywhere and they would magically look good. It took us less than a couple weeks to push this to production and make our app mostly responsive.\nBut with time, it became increasingly obvious that this was not as performant as we had hoped. It wasn\u2019t performant at all. Components would jarringly jump around the page before settling in on first paint.\nIt was only when we started using the flex-wrap: wrap CSS property to build new components that we realized we were not using the right language for the job. So we swapped out JavaScript container queries for CSS flex-wrapping. Even though flex wasn\u2019t yet as powerful as we wanted it to be, it was still a good compromise. Our components stayed independent of the window size but took much less time to render. Best of all: they used CSS instead of relying on JavaScript for layout.\nIn other words: we were using the wrong language to express our layout to the browser, when another language could do it much more simply and elegantly.\nLet\u2019s build a pattern library\u2026 in Ruby\nIn order to make our view layer maintainable, we chose to build a comprehensive library of helpers. This library would generate our markup from a single source of truth, allowing us to make changes system-wide, in one place. No. More. Grepping.\nWhen I joined Shopify it was a Rails shop freshly wounded by a JavaScript framework (See: Batman.js). JavaScript was like Voldemort, the language that could not be named. Because of this baggage, the only way for us to build a pattern library that would get buyin from our developers was to use Rails view helpers. And for many reasons using Ruby was the right choice for us. The time spent ramping developers up on the new UI Components would be negligible since the Ruby API felt familiar. The transition would be simple since we didn\u2019t have to introduce any new technology to the stack. The components would be fast since they would be rendered on the server. We had a plan.\nWe put in place a set of Rails tools to make it easy to build components, then wrote a bunch of sweet, sweet components using our shiny new tools. To document our design, content and front end patterns we put together an interactive styleguide to demonstrate how every component works. Our research and development department loved it (and still do)! We continue to roll out new components, and generally the project has been successful, though it has had its drawbacks.\nSince the Shopify admin is mostly made up of a huge number of forms, most of the content is static. For this reason, using server-rendered components didn\u2019t seem like a problem at the time. With new app features increasing the amount of DOM manipulation needed on the client side, our early design decisions mean making requests to the server for each re-paint. This isn\u2019t going to cut it.\nI don\u2019t know the end of this story, because we haven\u2019t written it yet. We\u2019ve been exploring alternatives to our current system to facilitate the rendering of our components on the client, including React, Vue.js, and Web Components, but we haven\u2019t determined the winner yet. Only time (and data gathering) will tell.\nRuby is great but it doesn\u2019t speak the browser\u2019s language efficiently. It was not the right language for the job.\n\nLearning a new spoken language has had an impact on how I write code. It has taught me that you don\u2019t know what you don\u2019t know until you have the language to express it. Understanding the strengths and limitations of any programming language is fundamental to making good design decisions. At the end of the day, you make the best choices with the information you have. But if you still feel like you\u2019re unable to express your thoughts to the fullest with what you know, it might be time to learn a new language.", "year": "2016", "author": "Annie-Claude C\u00f4t\u00e9", "author_slug": "annieclaudecote", "published": "2016-12-10T00:00:00+00:00", "url": "https://24ways.org/2016/watch-your-language/", "topic": "code"}
{"rowid": 293, "title": "A Favor for Your Future Self", "contents": "We tend to think about the future when we build things. What might we want to be able to add later? How can we refactor this down the road? Will this be easy to maintain in six months, a year, two years? As best we can, we try to think about the what-ifs, and build our websites, systems, and applications with this lens. \nWe comment our code to explain what we knew at the time and how that impacted how we built something. We add to-dos to the things we want to change. These are all great things! Whether or not we come back to those to-dos, refactor that one thing, or add new features, we put in a bit of effort up front just in case to give us a bit of safety later.\nI want to talk about a situation that Past Alicia and Team couldn\u2019t even foresee or plan for. Recently, the startup I was a part of had to remove large sections of our website. Not just content, but entire pages and functionality. It wasn\u2019t a very pleasant experience, not only for the reason why we had to remove so much of what we had built, but also because it\u2019s the ultimate \u201cI really hope this doesn\u2019t break something else\u201d situation. It was a stressful and tedious effort of triple checking that the things we were removing weren\u2019t dependencies elsewhere. To be honest, we wouldn\u2019t have been able to do this with any amount of success or confidence without our test suite.\nWriting tests for code is one of those things that developers really, really don\u2019t want to do. It\u2019s one of the easiest things to cut in the development process, and there\u2019s often a struggle to have developers start writing tests in the first place. One of the best lessons the web has taught us is that we can\u2019t, in good faith, trust the happy path. We must make sure ourselves, and our users, aren\u2019t in a tough spot later on because we only thought of the best case scenarios.\nJavaScript\nRegardless of your opinion on whether or not everything needs to be built primarily with JavaScript, if you\u2019re choosing to build a JavaScript heavy app, you absolutely should be writing some combination of unit and integration tests.\nUnit tests are for testing extremely isolated and small pieces of code, which we refer to as the units themselves. Great for reused functions and small, scoped areas, this is the closest you examine your code with the testing microscope. For example, if we were to build a calculator, the most minute piece we could test could be the basic operations.\n/*\n * This example uses a test framework called Jasmine\n */\n\ndescribe(\"Calculator Operations\", function () {\n\n    it(\"Should add two numbers\", function () {\n\n    // Say we have a calculator\n        Calculator.init();\n\n    // We can run the function that does our addition calculation...\n        var result = Calculator.addNumbers(7,3);\n\n    // ...and ensure we're getting the right output\n        expect(result).toBe(10);\n\n    });\n});\nEven though these teeny bits work in isolation, we should ensure that connecting the large pieces work, as well. This is where integration tests excel. These tests ensure that two or more different areas of code, that may not directly know about each other, still behave in expected ways. Let\u2019s build upon our calculator - we may want the operations to be saved in memory after a calculation runs. This isn\u2019t as suited for a unit test because there are a few other moving pieces involved in the process (the calculations, checking if the result was an error, etc.).\n    it(\u201cShould remember the last calculation\u201d, function () {\n\n    // Run an operation\n        Calculator.addNumbers(7,10);\n\n    // Expect something else to have happened as a result\n        expect(Calculator.updateCurrentValue).toHaveBeenCalled();\n        expect(Calculator.currentValue).toBe(17);\n    });\nUnit and integration tests provide assurance that your hand-rolled JavaScript should, for the most part, never fail in a grand fashion. Although it still might happen, you could be able to catch problems way sooner than without a test suite, and hopefully never push those failures to your production environment.\nInterfaces\nRegardless of how you\u2019re building something, it most definitely has some kind of interface. Whether you\u2019re using a very barebones structure, or you\u2019re leveraging a whole design system, these things can be tested as well.\nAcceptance testing helps us ensure that users can get from point A to point B within our web things, which can provide assurance that major features are always functioning properly. By simulating user input and data entry, we can go through whole user workflows to test for both success and failure scenarios. These are not necessarily for simulating edge-case scenarios, but rather ensuring that our core offerings are stable.\nFor example, if your site requires signup, you want to make sure the workflow is behaving as expected - allowing valid information to go through signup, while invalid information does not let you progress.\n/*\n * This example uses Jasmine along with an add-on called jasmine-integration\n */\n\ndescribe(\"Acceptance tests\", function () {\n\n  // Go to our signup page\n  var page = visit(\"/signup\");\n\n  // Fill our signup form with invalid information\n  page.fill_in(\"input[name='email']\", \"Not An Email\");\n  page.fill_in(\"input[name='name']\", \"Alicia\");\n  page.click(\"button[type=submit]\");\n\n  // Check that we get an expected error message\n  it(\"Shouldn't allow signup with invalid information\", function () {\n    expect(page.find(\"#signupError\").hasClass(\"hidden\")).toBeFalsy();\n  });\n\n  // Now, fill our signup form with valid information\n  page.fill_in(\"input[name='email']\", \"thisismyemail@gmail.com\");\n  page.fill_in(\"input[name='name']\", \"Gerry\");\n  page.click(\"button[type=submit]\");\n\n  // Check that we get an expected success message and the error message is hidden\n  it(\"Should allow signup with valid information\", function () {\n    expect(page.find(\"#signupError\").hasClass(\"hidden\")).toBeTruthy();\n    expect(page.find(\"#thankYouMessage\").hasClass(\"hidden\")).toBeFalsy();\n  });\n});\nIn terms of visual design, we\u2019re now able to take snapshots of what our interfaces look like before and after any code changes to see what has changed. We call this visual regression testing. Rather than being a pass or fail test like our other examples thus far, this is more of an awareness test, intended to inform developers of all the visual differences that have occurred, intentional or not. Developers may accidentally introduce a styling change or fix that has unintended side effects on other areas of a website - visual regression testing helps us catch these sooner rather than later. These do require a bit more consistent grooming than other tests, but can be valuable in major CSS refactors or if your CSS is generally a bit like Jenga.\nTools like PhantomCSS will take screenshots of your pages, and do a visual comparison to check what has changed between two sets of images. The code would look something like this:\n/*\n * This example uses PhantomCSS\n */\n\ncasper.start(\"/home\").then(function(){\n\n  // Initial state of form\n  phantomcss.screenshot(\"#signUpForm\", \"sign up form\");\n\n  // Hit the sign up button (should trigger error)\n  casper.click(\"button#signUp\");\n\n  // Take a screenshot of the UI component\n  phantomcss.screenshot(\"#signUpForm\", \"sign up form error\");\n\n  // Fill in form by name attributes & submit\n  casper.fill(\"#signUpForm\", {\n    name: \"Alicia Sedlock\",\n    email: \"alicia@example.com\"\n  }, true);\n\n  // Take a second screenshot of success state\n  phantomcss.screenshot(\"#signUpForm\", \"sign up form success\");\n});\nYou run this code before starting any development, to create your baseline set of screen captures. After you\u2019ve completed a batch of work, you run PhantomCSS again. This will create a second batch of screenshots, which are then put through an image comparison tool to display any differences that occurred. Say you changed your margins on our form elements \u2013 your image diff would look something like this:\n\nThis is a great tool for ensuring not just your site retains its expected styling, but it\u2019s also great for ensuring nothing accidentally changes in the living style guide or modular components you may have developed. It\u2019s hard to keep eagle eyes on every visual aspect of your site or app, so visual regression testing helps to keep these things monitored.\nConclusion\nThe shape and size of what you\u2019re testing for your site or app will vary. You may not need lots of unit or integration tests if you don\u2019t write a lot of JavaScript. You may not need visual regression testing for a one page site. It\u2019s important to assess your codebase to see which tests would provide the most benefit for you and your team.\nWriting tests isn\u2019t a joy for most developers, myself included. But I end up thanking Past Alicia a lot when there are tests, because otherwise I would have introduced a lot of issues into codebases. Shipping code that\u2019s broken breaks trust with our users, and it\u2019s our responsibility as developers to make sure that trust isn\u2019t broken. Testing shouldn\u2019t be considered a \u201cnice to have\u201d - it should be an integral piece of our workflow and our day-to-day job.", "year": "2016", "author": "Alicia Sedlock", "author_slug": "aliciasedlock", "published": "2016-12-03T00:00:00+00:00", "url": "https://24ways.org/2016/a-favor-for-your-future-self/", "topic": "code"}
{"rowid": 294, "title": "New Tricks for an Old Dog", "contents": "Much of my year has been spent helping new team members find their way around the expansive and complex codebase that is the TweetDeck front-end, trying to build a happy and productive group of people around a substantial codebase with many layers of legacy.\nI\u2019ve loved doing this. Everything from writing new documentation, drawing diagrams, and holding technical architecture sessions teaches you something you didn\u2019t know or exposes an area of uncertainty that you can go work on.\nIn this article, I hope to share some experiences and techniques that will prove useful in your own situation and that you can impress your friends in some new and exciting ways!\nHow do you do, fellow kids?\nTo start with I\u2019d like to introduce you to our JavaScript framework, Flight. Right now it\u2019s used by twitter.com and TweetDeck although, as a company, Twitter is largely moving to React.\nOver time, as we used Flight for more complex interfaces, we found it wasn\u2019t scaling with us.\nComposing components into trees was fiddly and often only applied for a specific parent-child pairing. It seems like an obvious feature with hindsight, but it didn\u2019t come built-in to Flight, and it made reusing components a real challenge.\nThere was no standard way to manage the state of a component; they all did it slightly differently, and the technique often varied by who was writing the code. This cost us in maintainability as you just couldn\u2019t predict how a component would be built until you opened it.\nMaking matters worse, Flight relied on events to move data around the application. Unfortunately, events aren\u2019t good for giving structure to complex logic. They jump around in a way that\u2019s hard to understand and debug, and force you to search your code for a specific string \u2014 the event name\u201a to figure out what\u2019s going on.\nTo find fixes for these problems, we looked around at other frameworks. We like React for it\u2019s simple, predictable state management and reactive re-render flow, and Elm for bringing strict functional programming to everyone.\nBut when you have lots of existing code, rewriting or switching framework is a painful and expensive option. You have to understand how it will interact with your existing code, how you\u2019ll test it alongside existing code, and how it will affect the size and performance of the application. This all takes time and effort!\nInstead of planning a rewrite, we looked for the ideas hidden within other frameworks that we could reapply in our own situation or bring to the tools we already were using.\nBoiled down, what we liked seemed quite simple:\n\nComponent nesting & composition\nEasy, predictable state management\nNormal functions for data manipulation\n\nMaking these ideas applicable to Flight took some time, but we\u2019re in a much better place now. Through persistent trial-and-error, we have well documented, testable and standard techniques for creating complex component hierarchies, updating and reacting to state changes, and passing data around the app.\nWhile the specifics of our situation and Flight aren\u2019t really important, this experience taught me something: \n\nDistill good tech into great ideas. You can apply great ideas anywhere.\n\nYou don\u2019t have to use cool kids\u2019 latest framework, hottest build tool or fashionable language to benefit from them. If you can identify a nugget of gold at the heart of it all, why not use it to improve what you have already?\nTimes, they are a changin\u2019\nApart from stealing ideas from the new and shiny, how can we keep make the most of improved tooling and techniques? Times change and so should the way we write code.\nGoing back in time a bit, TweetDeck used some slightly outmoded tools for building and bundling. Without a transpiler like Babel we were missing out new language features, and without a more advanced build tools like Webpack, every module\u2019s source was encased in AMD boilerplate.\nIn fact, we found ourselves with a mix of both AMD syntaxes:\ndefine([\"lodash\"], function (_) {\n  // . . .\n});\n\ndefine(function (require) {\n  var _ = require(\"lodash\");\n  // . . .\n});\nThis just wouldn\u2019t do. And besides, what we really wanted was CommonJS, or even ES2015 module syntax:\nimport _ from \"lodash\";\nThese days we\u2019re using Babel, Webpack, ES2015 modules and many new language features that make development just\u2026 better. But how did we get there?\nTo explain, I want to introduce you to codemods and jscodeshift.\nA codemod is a large-scale refactor of a whole codebase, often mechanical or repetitive. Think of renaming a module or changing an API like URL(\"...\") to new URL(\"...\").\njscodeshift is a toolkit for running automated codemods, where you express a code transformation using code. The automated codemod operates on each file\u2019s syntax tree \u2013 a data-structure representation of the code \u2014 finding and modifying in place as it goes.\nHere\u2019s an example that renames all instances of the variable foo to bar:\nmodule.exports = function (fileInfo, api) {\n  return api\n    .jscodeshift(fileInfo.source)\n    .findVariableDeclarators('foo')\n    .renameTo('bar')\n    .toSource();\n};\nIt\u2019s a seriously powerful tool, and we\u2019ve used it to write a series of codemods that:\n\nrename modules,\nunify our use of AMD to a single syntax,\ntransition from one testing framework to another, and\nswitch from AMD to CommonJS.\n\nThese changes can be pretty huge and far-reaching. Here\u2019s an example commit from when we switched to CommonJS:\ncommit 8f75de8fd4c702115c7bf58febba1afa96ae52fc\nDate:   Tue Jul 12 2016\n\n   Run AMD -> CommonJS codemod\n\n 418 files changed, 47550 insertions(+), 48468 deletions(-)\n\nYep, that\u2019s just under 50k lines changed, tested, merged and deployed without any trouble. AMD be gone!\n\nFrom this step-by-step approach,  using codemods to incrementally tweak and improve, we extracted a little codemod recipe for making significant, multi-stage changes:\n\nFind all the existing patterns\nChoose the two most similar\nUnify with a codemod\nRepeat.\n\nFor example:\n\nFor module loading, we had 2 competing AMD patterns plus some use of CommonJS\nThe two AMD syntaxes were the most similar\nWe used a codemod to move to unify the AMD patterns\nLater we returned to AMD to convert it to CommonJS\n\nIt\u2019s worked for us, and if you\u2019d like to know more about codemods then check out Evolving Complex Systems Incrementally by Facebook engineer, Christoph Pojer.\nWelcome aboard!\nAs TweetDeck has gotten older and larger, the amount of things a new engineer has to learn about has exploded. The myriad of microservices that manage our data and their layers of authentication, security and business logic around them make for an overwhelming amount of information to hand to a newbie.\nInspired by Amy\u2019s amazing Guide to the Care and Feeding of Junior Devs, we realised it was important to take time to design our onboarding that each of our new hires go through to make the most of their first few weeks.\nJoining a new company, team, or both, is stressful and uncomfortable. Everything you can do to help a new hire will be valuable to them. So please, take time to design your onboarding!\nAnd as you build up an onboarding process, you\u2019ll create things that are useful for more than just new hires; it\u2019ll force you to write documentation, for example, in a way that\u2019s understandable for people who are unfamiliar with your team, product and codebase. This can lead to more outside contributions: potential contributors feel more comfortable getting set up on your product without asking for help.\nThis is something that\u2019s taken for granted in open source, but somehow I think we forget about it in big companies.\nAfter all, better documentation is just a good thing. You will forget things from time to time, and you\u2019d be surprised how often the \u201cbeginner\u201d docs help!\nFor TweetDeck, we put together system and architecture diagrams, and one-pager explanations of important concepts:\n\nWhat are our dependencies?\nWhere are the potential points of failure?\nWhere does authentication live? Storage? Caching?\nWho owns \u201cX\u201d?\n\n\nOf course, learning continues long after onboarding. The landscape is constantly shifting; old services are deprecated, new APIs appear and what once true can suddenly be very wrong. Keeping up with this is a serious challenge, and more than any one person can track.\nTo address this, we\u2019ve thought hard about our knowledge sharing practices across the whole team. For example, we completely changed the way we do code review.\nIn my opinion, code review is the single most effective practice you can introduce to share knowledge around, and build the quality and consistency of your team\u2019s work. But, if you\u2019re not doing it, here\u2019s my suggestion for getting started:\n\nEvery pull request gets a +1 from someone else.\n\nThat\u2019s all \u2014 it\u2019s very light-weight and easy. Just ask someone to have a quick look over your code before it goes into master.\nAt Twitter, every commit gets a code review. We do a lot of reviewing, so small efficiency and effectiveness improvements make a big difference. Over time we learned some things:\n\nDon\u2019t review for more than hour 1\nKeep reviews smaller than ~400 lines 2\nCode review your own code first 2\n\nAfter an hour, and above roughly 400 lines, your ability to detect issues in a code review starts to decrease. So review little and often. The gaps around lunch, standup and before you head home are ideal. And remember, if someone\u2019s put code up for a review, that review is blocking them doing other work. It\u2019s your job to unblock them.\nOn TweetDeck, we actually try to keep reviews under 250 lines. It doesn\u2019t sound like much, but this constraint applies pressure to make smaller, incremental changes. This makes breakages easier to detect and roll back, and leads to a very natural feature development process that encourages learning and iteration.\nBut the most important thing I\u2019ve learned personally is that reviewing my own code is the best way to spot issues. I try to approach my own reviews the way I approach my team\u2019s: with fresh, critical eyes, after a break, using a dedicated code review tool.\nIt\u2019s amazing what you can spot when you put a new in a new interface around code you\u2019ve been staring at for hours!\nAnd yes, this list features science. The data backs up these conclusions, and if you\u2019d like to learn more about scientific approaches to software engineering then I recommend you buy Making Software: What Really Works, and Why We Believe It. It\u2019s ace.\nFor more dedicated information sharing, we\u2019ve introduced regular seminars for everyone who works on a specific area or technology. It works like this: a team-member shares or teaches something to everyone else, and next time it\u2019s someone else\u2019s turn. Giving everyone a chance to speak, and encouraging a wide range of topics, is starting to produce great results.\nIf you\u2019d like to run a seminar, one thing you could try to get started: run a point at the thing you least understand in our architecture session \u2014 thanks to James for this idea. And guess what\u2026 your onboarding architecture diagrams will help (and benefit from) this!\nMore, please!\nThere\u2019s a few ideas here to get you started, but there are even more in a talk I gave this year called Frontend Archaeology, including a look at optimising for confidence with front-end operations.\nAnd finally, thanks to Amy for proof reading this and to Passy for feedback on the original talk.\n\n\n\n\nDunsmore et al. 2000. Object-Oriented Inspection in the Face of Delocalisation. Beverly, MA: SmartBear Software.\u00a0\u21a9\n\n\nCohen, Jason. 2006. Best Kept Secrets of Peer Code Review. Proceedings of the 22nd ICSE 2000: 467-476.\u00a0\u21a9 \u21a9", "year": "2016", "author": "Tom Ashworth", "author_slug": "tomashworth", "published": "2016-12-18T00:00:00+00:00", "url": "https://24ways.org/2016/new-tricks-for-an-old-dog/", "topic": "code"}
{"rowid": 295, "title": "Internet of Stranger Things", "contents": "This year I\u2019ve been running a workshop about using JavaScript and Node.js to work with all different kinds of electronics on the Raspberry Pi. So especially for 24 ways I\u2019m going to show you how I made a very special Raspberry Pi based internet connected project! And nothing says Christmas quite like a set of fairy lights connected to another dimension1.\nWhat you\u2019ll see\nYou can rig up the fairy lights in your home, with the scrawly letters written under each one. The people from the other side (i.e. the internet) will be able to write messages to you from their browser in real time. In fact why not try it now; check this web page. When you click the lights in your browser, my lights (and yours) will turn on and off in real life! (There may be a queue if there are lots of people accessing it, hit the \u201cSend a message\u201d button and wait your turn.)\n\n\n\n\nIt\u2019s all done with JavaScript, using Node.js running on both the Raspberry Pi and on the server. I\u2019m using WebSockets to communicate in real time between the browser, server and Raspberry Pi.\nWhat you\u2019ll need\n\nRaspberry Pi any of the following models: Zero (will need straight male header pins soldered2 and Micro USB OTG adaptor), A+, B+, 2, or 3\nMicro SD card at least 4Gb Class 10 speed3\nMicro USB power supply at least 2A\nUSB Wifi dongle (unless you have a Pi 3 - that has wifi built in). \nAddressable fairy lights\nLogic level shifter (with pins soldered unless you want to do it!)\nBreadboard\nJumper wires (3x male to male and 4x female to male)\n\nOptional but recommended\n\nBase board to hold the Pi and Breadboard (often comes with a breadboard!)\n\nFind links for where to buy all of these items that goes along with this tutorial. The total price should be around $1004.\nSetting up the Raspberry Pi\nYou\u2019ll need to install the SD card for the Raspberry Pi. You\u2019ll find a link to download a disk image on the support document, ready-made with the Raspbian version of Linux, along with Node.js and all the files you need. Download it and write it to the SD card using the fantastic free software Etcher5. \nNext up you have to configure the wifi details on the SD card. If you plug the card into your computer you should see a drive called BOOT. There\u2019s a text file on there called wpa_supplicant.conf. Open it up in your favourite text editor and replace mywifi and mypassword with your wifi details6.\nnetwork={\n   ssid=\"mywifi\"\n   psk=\"mypassword\"\n}\nSave the file, eject the card from your computer and plug it into the Raspberry Pi. \nIf you have a base board or holder for the Raspberry Pi, attach it now. Then connect the wifi USB dongle7 and power supply, but don\u2019t plug it in yet!\nWiring!\nTime to wire everything up! \nFirst of all, push the Logic Level Converter into the middle of the breadboard:\n\nLogic Level Converter\nThe logic level converter may be labelled differently from the one in the diagram but the pins are usually exactly the same internally. I would just make sure the pins marked HV (High Voltage) are on the bottom and LV (Low Voltage) are on the top. \n\nRaspberry Pi pins only output 3.3v but the lights need 5v. That\u2019s why we need the logic level converter in there to boost up the signal.\nConnect the first two wires between the Raspberry Pi pins and the breadboard:\n\nNote that the pins on the Raspberry Pi are male, so you need a female to male jumper wire to connect between them and the breadboard. The colours don\u2019t have to match but it\u2019s easier to follow (and check) if you use the same ones as in the diagram. \n\nThen the next two:\n\nThis is what you should have so far:\n\nLights\nNow to connect the lights! My ones have a connector with three holes in it that I can push jumper wires into, and hopefully yours will too! So I used the male-to-male jumper wires to connect them to the breadboard.\n\n\n\nMake sure that you connect the right end of the lights, mine has a male connector at the wrong end so it\u2019s impossible to do this, but double check.  \nAlso make sure that the holes in the light connector are the same as mine. To do this, follow the wires from the connector to the first light and look at the circuit board inside. You should just about be able to make out the connections labelled + (sometimes 5V, V+ or VCC), GND (or \u2018-\u2019 or G) and DI (sometimes DIN for data in).\n\nYou can just about make out the +, DI and GND on this picture. Note that on the other side of the board there is a DO for data out - that\u2019s what takes the data along to the chip in the next light. Make sure that you\u2019re plugging into the data-in and not the data-out! \nThat\u2019s it! Everything\u2019s plugged in and ready to go! But before you plug power into your Pi, double check all your wires and make sure they\u2019re exactly right! You could damage your Raspberry Pi if it is not wired correctly. So triple check!\n\nThe Moment of Truth!\nPlug in the Raspberry Pi and wait around a minute or two for it to boot up. If all is well, the lights should strobe rainbow colours for one second - that\u2019s your confirmation that it\u2019s connected to my WebSocket server and ready to receive messages from the upside-down! \n\nHowever, if the first light in the string is pulsing red, it means that you\u2019re not connected to the internet. So check the Troubleshooting section of the support document. If it\u2019s pulsing green then you\u2019re connected to the internet but can\u2019t connect to my server. It must have gone down. Sorry! The code will keep trying so leave it running and maybe it\u2019ll come back up.  \nRig up the lights!\nFix the lights up on the wall however you want, pins, nails, tape. I\u2019ve used cable clips. Just be careful! I\u2019m using a 50 light string so I\u2019ve programmed it to use the lights at the end for the letters. That way I have just under half the string to extend down to the floor where I can keep the Raspberry Pi. \nCheck the photo here to see how the lights line up, note that there are spare unused lights in-between each row:\n\nNow visit lights.seb.ly and you\u2019ll see this : \n\nIf you\u2019re the only one online you\u2019ll have direct connection to the lights and any letter you click on will light up both in the browser and in real life. If there are other people there, you\u2019ll need to click the button to join the queue and wait your turn. \nHow it works - the geeky details!\nElectronics:\nThe pins on the Raspberry Pi are known as GPIO pins, general-purpose input/output. You can connect a wide variety of electronic components to them, LED lights, buttons, switches, and sensors. You can turn the power to the pins on and off using Node.js (or Python, if you prefer). \nAddressable LEDs or \u201cNeopixels\u201d\nWe\u2019re only using one GPIO pin on the Raspberry Pi (the other connections are 5V, 3.3V and ground) and that single pin is controlling all of the lights in the string. The code turns the pin on and off really fast in strictly timed morse-code-like dots and dashes to transmit binary data. The chips attached to each LED decode the binary and adjust the output to the LED accordingly. That chip then sends the data on to the next light in the string. \nThe chips on each light are the WS2811, part of the WS281x family that come in a multitude of different form factors and are often packaged with tiny LEDs in a single component. They are commonly referred to as Neopixels8 and I used them on my Laser Light Synths project.\nNeopixels with the chip and the LED all in one - it\u2019s the white square shaped component and the darker square inside is the chip. These are only 5mm wide!\nA Laser Light Synth! Covered with around 800 super bright neopixels!\nLogic Level Converter\nThe logic level converter is a really cheap and easy way to change the level from 3.3v to 5v and back again. You must be careful that you do not connect 5v into a GPIO pin or you will most likely damage the Raspberry Pi processor chip. \nPower\nNeopixels can often draw a lot of current so you need to be careful how you power them. I\u2019ve measured the current draw from the string to be less than 800mA so you should be fine wired directly to the 5V output. But if you use more lights or have them all on really bright at once, you\u2019ll need to use a separate 5V power supply. If you want to learn more, check out Adafruit\u2019s Neopixel Uberguide. \nNode.js\nThere are two Node.js apps running here, one on the Raspberry Pi and one on my server. You can see the code on my GitHub at github.com/sebleedelisle/stranger-lights for the Raspberry Pi and github.com/sebleedelisle/stranger-lights-server for the server.  And they\u2019re hosted on npm as stranger-lights and stranger-lights-server.  \nThe server side code sets up a standard web server to deliver the HTML for the web interface. It also sets up a WebSocket server that allows for real-time communication between the browser and the server. This server code also manages the queue and who is in control of the lights at any given time.\nWebSockets\nI\u2019m using the excellent Socket.io library to manage the WebSocket connection. Both the browser and the Raspberry Pi Node.js app connects to my WebSocket server. \nWhen you click on a letter in the browser, a message is sent to the server, which forwards it to the connected Raspberry Pi clients and also all the web browsers9. \nThe Raspberry Pi code\nThe Node.js app runs automatically on startup, and I made this happen by adding this to the /etc/rc.local file: \nnode /home/pi/strangerthings/client.js > /dev/null &\nAnything in the rc.local file gets executed when the Pi boots up and this line of code runs the Node.js app and routes its output to nowhere (ie /dev/null). The & means that it runs it in the background and doesn\u2019t hold up the boot process. \nWorking with the Raspberry Pi headless\nYou might know that when a computer has no screen or keyboard, you would refer to it as \u201crunning headless\u201d. So just like most web servers, you need to configure it over the network with ssh10. If you\u2019re on a mac you can find your Pi on the network through the name raspberrypi.local11, otherwise you\u2019ll need to find its IP address. There\u2019s more on the guide to Remote Access instructions on the Raspberry Pi website. And if you\u2019re very new to the terminal, I highly recommend this great online Linux command line tutorial.\nImprovements\nThis is quite an early experiment and I\u2019m sure I\u2019ll discover lots of optimisations over the next few weeks, especially if the server gets a proper hammering today! But there are a few things you can do. Obviously I\u2019ve just rigged up my lights with Post-it notes. It\u2019d be a lot nicer to get a paint brush and try to recreate the Winona-in-a-manic-state text style. \nWhere next?\nFinding quality resources about Node.js for electronics on the Pi can be somewhat hit and miss, but this is getting better all the time. Alternatively I am thinking about running some online courses, please let me know if that\u2019s something you\u2019d be interested in, or sign up to my mailing list at st4i.com. \nThere are many many more resources for the Raspberry Pi with Python (gpiozero is a good place to start), so if that language works for you, you\u2019ll be spoilt for choice! \nAlso take a look at Arduino - it\u2019s an incredibly popular platform for electronics and the internet is literally bursting with resources. \nI hope you enjoyed this little foray into the world of JavaScript electronics on the Raspberry Pi! If you get this working at home please let me know! Tweet me at @seb_ly. \n\n\n\n\nNot a particularly original idea, but I don\u2019t think I\u2019ve seen anyone do it quite like this before, ie using WebSockets, and Node.js on a Raspberry Pi. Other examples: Internet of Stranger Things, Strangerlights.com, and loads of examples on Instructables\u00a0\u21a9\ufe0e\n\n\nVideo guide to soldering pins on to a Pi Zero and further soldering advice from Adafruit\u00a0\u21a9\ufe0e\n\n\nSlower cards will work but performance may suffer\u00a0\u21a9\ufe0e\n\n\nOr \u00a35,000 in UK money. Sorry, Brexit joke :)\u00a0\u21a9\ufe0e\n\n\nYou will need a card reader on your computer - most micro SD cards come with an adaptor that fits standard SD slots. \u00a0\u21a9\ufe0e\n\n\nSSID and password should be all that you need but you can see all the config options on this wpa supplicant guide\u00a0\u21a9\ufe0e\n\n\nRaspberry Pi Zero will require the OTG to USB adaptor to attach the wifi dongle\u00a0\u21a9\ufe0e\n\n\nThanks to Adafruit who invented the term neopixels so we don\u2019t have to refer to them as WS281x any more!\u00a0\u21a9\ufe0e\n\n\nSo you can see other people sending messages in the browser\u00a0\u21a9\ufe0e\n\n\nssh is short for Secure Shell and is a way to connect to a remote computer and type in it just like you would in the terminal.\u00a0\u21a9\ufe0e\n\n\nYou can change this default hostname using raspi-config\u00a0\u21a9\ufe0e", "year": "2016", "author": "Seb Lee-Delisle", "author_slug": "sebleedelisle", "published": "2016-12-01T00:00:00+00:00", "url": "https://24ways.org/2016/internet-of-stranger-things/", "topic": "code"}
{"rowid": 296, "title": "Animation in Design Systems", "contents": "Our modern front-end workflow has matured over time to include design systems and component libraries that help us stay organized, improve workflows, and simplify maintenance. These systems, when executed well, ensure proper documentation of the code available and enable our systems to scale with reduced communication conflicts. \nBut while most of these systems take a critical stance on fonts, colors, and general building blocks, their treatment of animation remains disorganized and ad-hoc. Let\u2019s leverage existing structures and workflows to reduce friction when it comes to animation and create cohesive and performant user experiences. \nUnderstand the importance of animation\nPart of the reason we treat animation like a second-class citizen is that we don\u2019t really consider its power. When users are scanning a website (or any environment or photo), they are attempting to build a spatial map of their surroundings. During this process, nothing quite commands attention like something in motion. \nWe are biologically trained to notice motion: evolutionarily speaking, our survival depends on it. For this reason, animation when done well can guide your users. It can aid and reinforce these maps, and give us a sense that we understand the UX more deeply. We retrieve information and put it back where it came from instead of something popping in and out of place. \n\n\u201cWhere did that menu go? Oh it\u2019s in there.\u201d \n\nFor a deeper dive into how animation can connect disparate states, I wrote about the Importance of Context-Shifting in UX Patterns for CSS-Tricks.\nAn animation flow on mobile.\nAnimation also aids in perceived performance. Viget conducted a study where they measured user engagement with a standard loading GIF versus a custom animation. Customers were willing to wait almost twice as long for the custom loader, even though it wasn\u2019t anything very fancy or crazy. Just by showing their users that they cared about them, they stuck around, and the bounce rates dropped.\n\n14 second generic loading screen.22 second custom loading screen.\nThis also works for form submission. Giving your personal information over to an online process like a static form can be a bit harrowing. It becomes more harrowing without animation used as a signal that something is happening, and that some process is completing. That same animation can also entertain users and make them feel as though the wait isn\u2019t as long. \nEli Fitch gave a talk at CSS Dev Conf called: \u201cPerceived Performance: The Only Kind That Really Matters\u201d, which is one of my favorite talk titles of all time. In it, he discussed how we tend to measure things like timelines and network requests because they are more quantifiable\u2013and therefore easier to measure\u2013but that measuring how a user feels when visiting the site is more important and worth the time and attention. \nIn his talk, he states \u201cHumans over-estimate passive waits by 36%, per Richard Larson of MIT\u201d. This means that if you\u2019re not using animation to speed up how fast the wait time of a form submission loads, users are perceiving it to be much slower than the dev tools timeline is recording.\nReign it in\nUnlike fonts, colors, and so on, we tend to add animation in as a last step, which leads to disorganized implementations that lack overall cohesion. If you asked a designer or developer if they would create a mockup or build a UI without knowing the fonts they were working with, they would dislike the idea. Not knowing the building blocks they\u2019re working with means that the design can fall apart or the development can break with something so fundamental left out at the start. Good animation works the same way.\nThe first step in reigning in your use of animation is to perform an animation audit. Look at all the places you are using animation on your site, or the places you aren\u2019t using animation but probably should. (Hint: perceived performance of a loader on a form submission can dramatically change your bounce rates.) \nNot sure how to perform a good audit? Val Head has a great chapter on it in her book, Designing Interface Animations, which has of buckets of research and great ideas.\nEven some beautiful component libraries that have animation in the docs make this mistake. You don\u2019t need every kind of animation, just like you don\u2019t need every kind of font. This bloats our code. Ask yourself questions like: do you really need a flip 180 degree animation? I can\u2019t even conceive of a place on a typical UI where that would be useful, yet most component libraries that I\u2019ve seen have a mixin that does just this.\nWhich leads to\u2026\nHave an opinion\nMany people are confused about Material Design. They think that Material Design is Motion Design, mostly because they\u2019ve never seen anyone take a stance on animation before and document these opinions well. But every time you use Material Design as your motion design language, people look at your site and think GOOGLE. Now that\u2019s good branding.\nBy using Google\u2019s motion design language and not your own, you\u2019re losing out on a chance to be memorable on your own website.\nWhat does having an opinion on motion look like in practice? It could mean you\u2019ve decided that you never flip things. It could mean that your eases are always going to glide. In that instance, you would put your efforts towards finding an ease that looks \u201cgliding\u201d and pulling out any transform: scaleX(-1) animation you find on your site. Across teams, everyone knows not to spend time mocking up flipping animation (even if they\u2019re working on an entirely different codebase), and to instead work on something that feels like it glides. You save time and don\u2019t have to communicate again and again to make things feel cohesive.\nCreate good developer resources\nSometimes people don\u2019t incorporate animation into a design system because they aren\u2019t sure how, beyond the base hover states. All animation properties can be broken into interchangeable pieces. This allows developers and designers alike to mix and match and iterate quickly, while still staying in the correct language. Here are some recommendations (with code and a demo to follow):\nCreate timing units, similar to h1, h2, h3. In a system I worked on recently, I called these t1, t2, t3. T1 would be reserved for longer pieces, down to t5 which is a bit like h5 in that it\u2019s the default (usually around .25 seconds or thereabouts).\nKeep animation easings for entrance, exit, entrance emphasis and exit emphasis that people can commonly refer to. This, and the animation-fill-mode, are likely to be the only two properties that can be reused for the entrance and exit of the animation.\nUse the animation-name property to define the keyframes for the animation itself. I would recommend starting with 5 or 6 before making a slew of them, and see if you need more. Writing 30 different animations might seem like a nice resource, but just like your color palette having too many can unnecessarily bulk up your codebase, and keep it from feeling cohesive. Think critically about what you need here. \nSee the Pen Modularized Animation for Component Libraries by Sarah Drasner (@sdras) on CodePen.\n\nThe example above is pared-down, but you can see how in a robust system, having pieces that are interchangeable cached across the whole system would save time for iterations and prototyping, not to mention make it easy to make adjustments for different feeling movement on the same animation easily.\nOne low hanging fruit might be a loader that leads to a success dialog. On a big site, you might have that pattern many times, so writing up a component that does only that helps you move faster while also allowing you to really zoom in and focus on that pattern. You avoid throwing something together at the last minute, or using a GIF, which are really heavy and mushy on retina. You can make singular pieces that look really refined and are reusable. \nReact and Vue Implementations are great for reusable components, as you can create a building block with a common animation pattern, and once created, it can be a resource for all. Remember to take advantage of things like props to allow for timing and easing adjustments like we have in the previous example!\nResponsive\nAt the very least we should ensure that interaction also works well on mobile, but if we\u2019d like to create interactions that take advantage of all of the gestures mobile has to offer, we can use libraries like zingtouch or hammer to work with swipe or multiple finger detection. With a bit of work, these can all be created through native detection as well.\nResponsive web pages can specify initial-scale=1.0 in the meta tag so that the device is not waiting the required 300ms on the secondary tap before calling action. Interaction for touch events must either start from a larger touch-target (40px \u00d7 40px or greater) or use @media(pointer:coarse) as support allows.\nBuy-in\nSometimes people don\u2019t create animation resources simply because it gets deprioritized. But design systems were also something we once had to fight for, too. This year at CSS Dev Conf, Rachel Nabors demonstrated how to plot out animation wants vs. needs on a graph (reproduced with her permission) to help prioritize them:\n\n\nThis helps people you\u2019re working with figure out the relative necessity and workload of the addition of these animations and think more critically about it. You\u2019re also more likely to get something through if you\u2019re proving that what you\u2019re making is needed and can be reused. \nGood compromises can be made this way: \u201cwe\u2019re not going to go all out and create an animated \u2018About Us\u2019 page like you wanted, but I suppose we can let our users know their contact email went through with a small progress and success notification.\u201d \nSuccessfully pushing smaller projects through helps build trust with your team, and lets them see what this type of collaboration can look like. This builds up the type of relationship necessary to push through projects that are more involved. It can\u2019t be overstressed that good communication is key.\nGet started!\nWith these tools and good communication, we can make our codebases more efficient, performant, and feel better for our users. We can enhance the user experience on our sites, and create great resources for our teams to allow them to move more quickly while innovating beautifully.", "year": "2016", "author": "Sarah Drasner", "author_slug": "sarahdrasner", "published": "2016-12-16T00:00:00+00:00", "url": "https://24ways.org/2016/animation-in-design-systems/", "topic": "code"}
{"rowid": 298, "title": "First Steps in VR", "contents": "The web is all around us. As web folk, it is our responsibility to consider the impact our work can have. Part of this includes thinking about the future; the web changes lives and if we are building the web then we are the ones making decisions that affect people in every corner of the world. I find myself often torn between wanting to make the right decisions, and just wanting to have fun. To fiddle and play. We all know how important it is to sometimes just try ideas, whether they will amount to much or not. \nI think of these two mindsets as production and prototyping, though of course there are lots of overlap and phases in between. I mention this because virtual reality is currently seen as a toy for rich people, and in some ways at the moment it is. But with WebVR we are able to create interesting experiences with a relatively low entry point. I want us to have open minds, play around with things, and then see how we can use the tools we have at our disposal to make things that will help people.\nEvery year we see articles saying it will be the \u201cyear of virtual reality\u201d, that was especially prevalent this year. 2016 has been a year of progress, VR isn\u2019t quite mainstream but with efforts like Playstation VR and Google Cardboard, we are definitely seeing much more of it. This year also saw the consumer editions of the Oculus Rift and HTC Vive. So it does seem to be a good time for an overview of how to get involved with creating virtual reality on the web.\nWebVR is an API for connecting to devices and retrieving continuous data such as the position and orientation. Unlike the Web Audio API and some other APIs, WebVR does not feel like a framework. You use it however you want, taking the data and using it as you wish. To make it easier, there are plenty of resources such as Three.js, A-Frame and ReactVR that help to make the heavy lifting a bit easier.\nGetting Started with A-Frame\nI like taking the opportunity to learn new things whenever I can. So while planning this article I thought that instead of trying to teach WebGL or even Three.js in a way that is approachable for all, I would create my first project using A-Frame and write about that. This is not a tutorial as such, I just want to show how to go about getting involved with VR. The beauty of A-Frame is that it is very similar to web components, you can just write HTML to build worlds that will automatically work on all the different types of devices. It uses WebGL and WebVR but in such a way that it quite drastically reduces the learning curve. That\u2019s not to say you can\u2019t build complex things, you have complete access to write JavaScript and shaders.\nI\u2019m lazy. Whenever I learn a new language or framework I have found that the best way, personally, for me to learn is to have a project and to copy the starting code from someone else. A project lets you have a good idea of what you want to produce and it means you can ignore a lot of the irrelevant documentation, focussing purely on what you need. That reduces the stress of figuring things out. Copying code also makes it easier, because you know your boilerplate code is working. There\u2019s nothing worse than getting stuck before anything actually works the first time. So I tinker. I take code and I modify it, I play around. It\u2019s fun.\nFor this project I wanted to keep things as simple as possible, so I can easily explain it without the classic \u201cdraw a circle then draw an owl\u201d. I wrote a list of requirements, with some stretch goals that you can give a try yourself if you fancy:\n\nMust work on Google Cardboard at a minimum, because of price\nTherefore, it must not rely on having a controller\nAuto-moving around a maze would be a good example\nMove in direction you look\nStretch goal: Scoring, time until you hit a wall or get stuck in maze\nStretch goal: Levels, so the map doesn\u2019t need to be random\nStretch goal: Snow!\n\nI decided to  base this project on an example, Platforms, by Don McCurdy who wrote the really useful aframe-extras. Platforms has random 3D blocks that you can jump onto, going up into the sky. So I took his code and reduced it so that the blocks are randomly spread on the ground. \n<!DOCTYPE html>\n<html>\n<head>\n    <meta charset=\"utf-8\">\n    <meta name=\"viewport\" content=\"width=device-width\">\n    <title>24 ways</title>\n    <script src=\"https://aframe.io/releases/0.3.2/aframe.js\"></script>\n    <script src=\"//cdn.rawgit.com/donmccurdy/aframe-extras/v2.6.1/dist/aframe-extras.min.js\"></script>\n</head>\n<body>\n<a-scene>\n    <a-entity id=\"player\"\n              camera\n              universal-controls\n              kinematic-body\n              position=\"0 1.8 0\">\n    </a-entity>\n\n    <a-entity id=\"walls\"></a-entity>\n\n    <a-grid id=\"ground\" static-body></a-grid>\n\n    <a-sky id=\"sky\" color=\"#AADDF0\"></a-sky>\n\n    <!-- Lighting -->\n    <a-light type=\"ambient\" color=\"#ccc\"></a-light>\n</a-scene>\n<script>\n    document.querySelector('a-scene').addEventListener('render-target-loaded', function () {\n        var MAP_SIZE = 10,\n                PLATFORM_SIZE = 5,\n                NUM_PLATFORMS = 50;\n        var platformsEl = document.querySelector('#walls');\n        var v, box;\n        for (var i = 0;  i < NUM_PLATFORMS; i++) {\n            // y: 0 is ground\n            v = {\n                x: (Math.floor(Math.random() * MAP_SIZE) - PLATFORM_SIZE) * PLATFORM_SIZE,\n                y: PLATFORM_SIZE / 2,\n                z: (Math.floor(Math.random() * MAP_SIZE) - PLATFORM_SIZE) * PLATFORM_SIZE\n            };\n            box = document.createElement('a-box');\n            platformsEl.appendChild(box);\n            box.setAttribute('color', '#39BB82');\n            box.setAttribute('width', PLATFORM_SIZE);\n            box.setAttribute('height', PLATFORM_SIZE);\n            box.setAttribute('depth', PLATFORM_SIZE);\n            box.setAttribute('position', v.x + ' ' + v.y + ' ' + v.z);\n            box.setAttribute('static-body', '');\n        }\n        console.info('Platforms loaded.');\n    });\n</script>\n</body>\n</html>\nAs you can see, this is very readable. Especially if you ignore the JavaScript that is used to create the maze. A-Frame (with A-Frame Extras) gives you a lot of power with relatively little to learn. We start with an <a-scene> which is the container for everything that is going to show up on the screen. There are a few <a-entity> which can be compared to <div> as they are essentially non-semantic containers, able to be used for any purpose. The attributes are used to define functionality, for example the camera attribute sets the entity to function as a camera and kinematic-body makes it collide instead of go through objects. Attributes are also used to set position and sizes, often using JavaScript to dynamically define them.\nStyling\nNow we\u2019ve got the HTML written, we need to style it. To do this we add A-Frame compatible attributes such as color and material. I recommend playing around, you can get some quite impressive effects fairly easily. Originally I wanted a light snowy maze but it ended up being dark and foggy, as I really liked the feeling it gave.\nNote, you will probably need a server running for images to work. You can do this by running python -m \"SimpleHTTPServer\" in the folder where the code is, then go to localhost:8000 in browser.\nTextures\nUnless you are going for a cartoony style, you probably want to find some textures. I found some on textures.com, one image worked well for the walls and the other for the floor.\n<a-assets>\n    <img id=\"texture-floor\" src=\"floor.jpg\">\n    <img id=\"texture-wall\" src=\"wall.jpg\">\n</a-assets>\nThe <a-assets> is used to define (as well as preload and cache) all assets, including images, audio and video. As you can see, images in the Asset Management System just use normal img tags. The ids are important here as we can use them later for using the textures. \nTo apply a texture to an object, you create a material. For a simple material where it just shows the image, you set the src to the id selector of the image.\nReplace: \n<a-grid id=\"ground\" static-body></a-grid>\nWith:\n<a-grid id=\"ground\" static-body material=\"src: #texture-floor\"></a-grid>\nThis will automatically make the image repeat over the entire floor, in my case filling it with bricks. The walls are pretty much identical, with the slight exception that it is set in JavaScript as they are dynamically defined.\nbox.setAttribute('material', 'src: #texture-wall');\nThat\u2019s it for the textures, for now at least. These will not look completely realistic, as the light will bump off the rectangular wall rather than texture itself. This can be improved by using maps, textures that are used to modify the shape and physical properties of the object. \nLighting\nThe next part of styling is lighting. By using fog and different types of lighting, we are able to add atmospheric details to the game to make it feel that bit more realistic and polished.\nThere are lots of types of light in A-Frame (most coming from Three.js). You can add a light either by using the <a-light> entity or by attaching a light attribute to any other entity. If there are no lights defined then A-Frame adds some by default so that the scene is always lit.\nTo start with I wanted to light up the scene with a general light, type=\"ambient\", so that the whole game felt slightly dark. I chose to set the light to a reddish colour #92455E. After playing around with intensity I chose 0.4, it added enough light to get the feeling I wanted without it being overly red. I also added a blue skybox (<a-sky>), as it looked a bit odd with a white sky.\n<a-light type=\"ambient\" color=\"#92455E\" intensity=\"0.4\"></a-light>\n<a-sky id=\"sky\" color=\"#0000ff\"></a-sky>\nI felt that the maze looked good with a red tinge but it was a bit flat, everything was the same colour and it was a bit dark. So I added a light within the #player entity, this could have been as an attribute but I set it as a child a-light instead. By using type=\"point\" with a high intensity and low distance, it showed close walls as being lighter. It also added a sort-of object to the player, it isn\u2019t a walking human or anything but by moving light where the player is it feels a bit more physical.\n<a-light color=\"#fff\" distance=\"5\" intensity=\"0.7\" type=\"point\"></a-light>\n\nBy this point it was starting to look decent, so I wanted to add the fog to really give some personality and depth to the maze. To do this I added the fog attribute to the <a-scene> with type=exponential so it looks thicker the further away it is and a mid intensity, so you feel a bit lost but can still see.\n\nI was very happy with this result. It took a lot of playing around with colours and values, which is fun in itself. I highly recommend you take the code (or write your own) and play around with the numbers.\nMovement\nOne of the reasons I decided to use aframe-extras is that it has a few different camera controls built in. As you saw earlier, I am using the universal-controls which gives WASD (keyboard) controls by default. I wanted to make it automatically move in the direction that you\u2019re looking, but I wasn\u2019t quite sure how without rewriting the controls. So I asked Don McCurdy for advice and he very nicely gave me a small snippet of code to get it working.\nAFRAME.registerComponent('automove-controls', {\n    init: function () {\n        this.speed = 0.1;\n        this.isMoving = true;\n        this.velocityDelta = new THREE.Vector3();\n    },\n    isVelocityActive: function () {\n        return this.isMoving;\n    },\n    getVelocityDelta: function () {\n        this.velocityDelta.z = this.isMoving ? -speed : 0;\n        return this.velocityDelta.clone();\n    }\n});\nReplace:\nuniversal-controls\nWith:\nuniversal-controls=\"movementControls: automove, gamepad, keyboard\"\nThis works by creating a component automove-controls that adds auto-move to the player without overriding movement completely. It doesn\u2019t even touch direction, it just checks if isMoving is true then moves the player by the set speed. Components can be creating for adding all kinds of functionality with relative ease. It makes it very powerful for people of all difficulty levels.\nBuilding a map\nCurrently the maze is created randomly, which is great but means there will often be walls that overlap or the player gets trapped with nowhere to go. So to solve this, I decided to use a map editor (Tiled) so that we can create the mazes ourselves. This is a great start towards one of the stretch goals, levels.\nI made the maze in Tiled by finding a random tileset online (we don\u2019t need to actually show the images), I used one tile for the wall and another for the player. Then I exported as a JavaScript file and modified it in my text editor to get rid of everything I didn\u2019t need. I made it so 0 is the path, 1 is the wall and 2 is the player. I then added the script to the HTML, as a separate file so it\u2019s easy to update in the future. \nvar map =\n{\n \"data\":[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],\n \"height\":10,\n \"width\":10\n}\n\nAs you can see, this gives a simple 10x10 maze with some dead ends. The player starts in the bottom right corner (my choice, could be anywhere). I rewrote the random platforms code (from Don\u2019s example) to instead loop over the map data and place walls where it is 1 and position the player where data is 2. I set the position so that the origin of the map would be 0,1.5,0. The y axis is in this case the height (ground being 0), but if a wall is positioned at 0 by its centre then some of it is underground. So the y needed to be the height divided by 2.\ndocument.querySelector('a-scene').addEventListener('render-target-loaded', function () {\n    var WALL_SIZE = 5,\n        WALL_HEIGHT = 3;\n    var el = document.querySelector('#walls');\n    var wall;\n\n    for (var x = 0; x < map.height; x++)  {\n        for (var y = 0; y < map.width; y++) {\n\n            var i = y*map.width + x;\n            var position = (x-map.width/2)*WALL_SIZE + ' ' + 1.5 + ' ' + (y-map.height/2)*WALL_SIZE;\n            if (map.data[i] === 1) {\n                // Create wall\n                wall = document.createElement('a-box');\n                el.appendChild(wall);\n                wall.setAttribute('color', '#fff');\n                wall.setAttribute('material', 'src: #texture-wall;');\n                wall.setAttribute('width', WALL_SIZE);\n                wall.setAttribute('height', WALL_HEIGHT);\n                wall.setAttribute('depth', WALL_SIZE);\n                wall.setAttribute('position', position);\n                wall.setAttribute('static-body', ');\n            }\n\n            if (map.data[i] === 2)  {\n                // Set player position\n                document.querySelector('#player').setAttribute('position', position);\n            }\n\n        }\n    }\n    console.info('Walls added.');\n});\n\nWith this added, it makes it nice and easy to change around the map as well as to add new features. Perhaps you want monsters or objects. Just set the number in the map data and add an if statement to the loop. In the future you could add layers, so multiple things can be in the same position. Or perhaps even make the maze go up the y axis too, with ramps or staircases. There\u2019s a lot you can do with relative ease. As you can see, A-Frame really does reduce the learning curve of 3D and VR on the web.\nIt\u2019s Not All Fun And Games\nA lot of examples of virtual reality are games, including this one. So it is understandable to think that VR is for gaming, but actually that\u2019s just a tiny subset. There are all sorts of applications for VR, including story telling, data visualisation and even meditation.\nThere have been a number of cases where it has been shown virtual reality can help as a tool for therapies:\n\nOxford study finds virtual reality can help treat severe paranoia\nVirtual Reality Therapy for Phobias at the Duke Faculty Practice\nBravemind: Virtual Reality Exposure Therapy at the University of Southern California\n\nThese are just a few examples of where virtual reality is being used around the world to help people feel better and get through some very tough times. There have also been examples of it being used for simulating war zones or medical situations, both as a teaching and journalism tool.\nWrapping Up\nTen years ago, on this very site, Cameron Moll wrote an article explaining the mobile web. He explained how mobile phones with data plans were becoming increasingly common, that WAP 2.0 included the XHTML Mobile Profile meaning it would be familiar with web folk. \u201cThe mobile web is rapidly becoming an XHTML environment, and thus you and I can apply our existing \u201cdesktop web\u201d skills to understand how to develop content for it.\u201d\nWe can look at that and laugh a little, we have come a very long way in the last decade. Even people in developing countries with very little money have mobile phones with access to a web that is far more capable than the \u201cdesktop web\u201d Cameron was referring to.\nSo while I am not saying virtual reality is going to change the world or replace our phones, who knows! We can use our skills as web folk to dabble, we don\u2019t need to learn any new languages. If on the 2026 edition of 24 ways, somebody references this article and looks at how far we have come\u2026 well, let\u2019s hope we have used our skills well and made the world just that little bit better. And if VR is a fad? Well it\u2019s fun\u2026 have a go anyway.", "year": "2016", "author": "Shane Hudson", "author_slug": "shanehudson", "published": "2016-12-11T00:00:00+00:00", "url": "https://24ways.org/2016/first-steps-in-vr/", "topic": "code"}
{"rowid": 300, "title": "Taking Device Orientation for a Spin", "contents": "When The Police sang \u201cDon\u2019t Stand So Close To Me\u201d they weren\u2019t talking about using a smartphone to view a panoramic image on Facebook, but they could have been. For years, technology has driven relentlessly towards devices we can carry around in our pockets, and now that we\u2019re there, we\u2019re expected to take the thing out of our pocket and wave it around in front of our faces like a psychotic donkey in search of its own dangly carrot.\nBut if you can\u2019t beat them, join them.\nA brave new world\nA couple of years back all sorts of specs for new HTML5 APIs sprang up much to our collective glee. Emboldened, we ran a few tests and found they basically didn\u2019t work in anything and went off disheartened into the corner for a bit of a sob.\nTurns out, while we were all busy boohooing, those browser boffins have actually being doing some work, and lo and behold, some of these APIs are even half usable. Mostly literally half usable\u2014we\u2019re still talking about browsers, after all.\nNow, of course they\u2019re all a bit JavaScripty and are going to involve complex methods and maths and science and probably about a thousand dependancies from Github that will fall out of fashion while we\u2019re still trying to locate the documentation, right? Well, no! \nSo what if we actually wanted to use one of these APIs, say to impress our friends with our ability to make them wave their phones in front of their faces (because no one enjoys looking hapless more than the easily-technologically-impressed), how could we do something like that? Let\u2019s find out.\nThe Device Orientation API\nThe phone-wavy API is more formally known as the DeviceOrientation Event Specification. It does a bunch of stuff that basically doesn\u2019t work, but also gives us three values that represent orientation of a device (a phone, a tablet, probably not a desktop computer) around its x, y and z axes. You might think of it as pitch, roll and yaw if you like to spend your weekends wearing goggles and a leather hat.\nThe main way we access these values is through an event listener, which can inform our code every time the value changes. Which is constantly, because you try and hold a phone still and then try and hold the Earth still too.\nThe API calls those pitch, roll and yaw values alpha, beta and gamma. Chocks away:\nwindow.addEventListener('deviceorientation', function(e) {\n    console.log(e.alpha);\n    console.log(e.beta);\n    console.log(e.gamma);\n});\nIf you look at this test page on your phone, you should be able to see the numbers change as you twirl the thing around your body like the dance partner you never had. Wrist strap recommended.\nOne important note\nLike may of these newfangled APIs, Device Orientation is only available over HTTPS. We\u2019re not allowed to have too much fun without protection, so make sure that you\u2019re working on a secure line. I\u2019ve found a quick and easy way to share my local dev environment over TLS with my devices is to use an ngrok tunnel.\nngrok http -host-header=rewrite mylocaldevsite.dev:80\nngrok will then set up a tunnel to your dev site with both HTTP and HTTPS URL options. You, of course, want the HTTPS option.\nRight, where were we?\nMake something to look at\nIt\u2019s all well and good having a bunch of numbers, but they\u2019re no use unless we do something with them. Something creative. Something to inspire the generations. Or we could just build that Facebook panoramic image viewer thing (because most of us are familiar with it and we\u2019re not trying to be too clever here). Yeah, let\u2019s just build one of those.\nOur basic framework is going to be similar to that used for an image carousel. We have a container, constrained in size, and CSS overflow property set to hidden. Into this we place our wide content and use positioning to move the content back and  forth behind the \u2018window\u2019 so that the part we want to show is visible.\nHere it is mocked up with a slider to set the position. When you release the slider, the position updates. (This actually tests best on desktop with your window slightly narrowed.)\nThe details of the slider aren\u2019t important (we\u2019re about to replace it with phone-wavy goodness) but the crucial part is that moving the slider results in a function call to position the image. This takes a percentage value (0-100) with 0 being far left and 100 being far right (or \u2018alt-nazi\u2019 or whatever).\nvar position_image = function(percent) {\n    var pos = (img_W / 100)*percent;\n    img.style.transform = 'translate(-'+pos+'px)'; \n};\nAll this does is figure out what that percentage means in terms of the image width, and set the transform: translate(\u2026); CSS property to move the image. (We use translate because it might be a bit faster to animate than left/right positioning.)\nOk. We can now read the orientation values from our device, and we can programatically position the image. What we need to do is figure out how to convert those raw orientation values into a nice tidy percentage to pass to our function and we\u2019re done. (We\u2019re so not done.)\nThe maths bit\nIf we go back to our raw values test page and make-believe that we have a fascinating panoramic image of some far-off beach or historic monument to look at, you\u2019ll note that the main value that is changing as we swing back and forth is the \u2018alpha\u2019 value. That\u2019s the one we want to track.\nAs our goal here is hey, these APIs are interesting and fun and not let\u2019s build the world\u2019s best panoramic image viewer, we\u2019ll start by making a few assumptions and simplifications:\n\nWhen the image loads, we\u2019ll centre the image and take the current nose-forward orientation reading as the middle.\nMoving left, we\u2019ll track to the left of the image (lower percentage).\nMoving right, we\u2019ll track to the right (higher percentage).\nIf the user spins round, does cartwheels or loads the page then hops on a plane and switches earthly hemispheres, they\u2019re on their own.\n\nNose-forward\nWhen the page loads, the initial value of alpha gives us our nose-forward position. In Safari on iOS, this is normalised to always be 0, whereas most everywhere else it tends to be bound to pointy-uppy north. That doesn\u2019t really matter to us, as we don\u2019t know which direction the user might be facing in anyway \u2014 we just need to record that initial state and then use it to compare any new readings.\nvar initial_position = null;\n\nwindow.addEventListener('deviceorientation', function(e) {\n    if (initial_position === null) {\n        initial_position = Math.floor(e.alpha);\n    };\n\n    var current_position = initial_position - Math.floor(e.alpha);\n});\n(I\u2019m rounding down the values with Math.floor() to make debugging easier - we\u2019ll take out the rounding later.)\nWe get our initial position if it\u2019s not yet been set, and then calculate the current position as a difference between the new value and the stored one.\nThese values are weird\nOne thing you need to know about these values, is that they range from 0 to 360 but then you also get weird left-of-zero values like -2 and whatever. And they wrap past 360 back to zero as you\u2019d expect if you do a forward roll.\nWhat I\u2019m interested in is working out my rotation. If 0 is my nose-forward position, I want a positive value as I turn right, and a negative value as I turn left. That puts the awkward 360-tipping point right behind the user where they can\u2019t see it.\nvar rotation  = current_position;\nif (current_position > 180) rotation = current_position-360;\nWhich way up?\nSince we\u2019re talking about orientation, we need to remember that the values are going to be different if the device is held in portrait on landscape mode. See for yourself - wiggle it like a steering wheel and you get different values. That\u2019s easy to account for when you know which way up the device is, but in true browser style, the API for that bit isn\u2019t well supported. The best I can come up with is:\nvar screen_portrait = false;\nif (window.innerWidth < window.innerHeight) {\n    screen_portrait = true;\n}\nIt works. Then we can use screen_portrait to branch our code:\nif (screen_portrait) {\n        if (current_position > 180) rotation = current_position-360;\n} else {\n        if (current_position < -180) rotation = 360+current_position;\n}\nHere\u2019s the code in action so you can see the values for yourself. If you change screen orientation you\u2019ll need to refresh the page (it\u2019s a demo!).\nLimiting rotation\nNow, while the youth of today are rarely seen without a phone in their hands, it would still be unreasonable to ask them to spin through 360\u00b0 to view a photo. Instead, we need to limit the range of movement to something like 60\u00b0-from-nose in either direction and normalise our values to pan the entire image across that 120\u00b0 range. -60 would be full-left (0%) and 60 would be full-right (100%).\nIf we set max_rotation = 60, that code ends up looking like this:\nif (rotation > max_rotation) rotation = max_rotation;\nif (rotation < (0-max_rotation)) rotation = 0-max_rotation;\n\nvar percent = Math.floor(((rotation + max_rotation)/(max_rotation*2))*100);\nWe should now be able to get a rotation from -60\u00b0 to +60\u00b0 expressed as a percentage. Try it for yourself.\nThe big reveal\nAll that\u2019s left to do is pass that percentage to our image positioning function and would you believe it, it might actually work.\nposition_image(percent);\nYou can see the final result and take it for a spin. Literally.\nSo what have we made here? Have we built some highly technical panoramic image viewer to aid surgeons during life-saving operations using only JavaScript and some slightly questionable mathematics? No, my friends, we have not. Far from it. \nWhat we have made is progress. We\u2019ve taken a relatively newly available hardware API and a bit of simple JavaScript and paired it with existing CSS knowledge and made something that we didn\u2019t have this morning. Something we probably didn\u2019t even want this morning. Something that if you take a couple of steps back and squint a bit might be a prototype for something vaguely interesting. But more importantly, we\u2019ve learned that our browsers are just a little bit more capable than we thought.\nThe web platform is maturing rapidly. There are new, relatively unexplored APIs for doing all sorts of crazy thing that are often dismissed as the preserve of native apps. Like some sort of app marmalade. Poppycock. \nThe web is an amazing, exciting place to create things. All it takes is some base knowledge of the fundamentals, a creative mind and a willingness to learn. We have those! So let\u2019s create things.", "year": "2016", "author": "Drew McLellan", "author_slug": "drewmclellan", "published": "2016-12-24T00:00:00+00:00", "url": "https://24ways.org/2016/taking-device-orientation-for-a-spin/", "topic": "code"}
{"rowid": 303, "title": "We Need to Talk About Technical Debt", "contents": "In my work with clients, a lot of time is spent assessing old, legacy, sprawling systems and identifying good code, bad code, and technical debt.\nOne thing that constantly strikes me is the frequency with which bad code and technical debt are conflated, so let me start by saying this:\nNot all technical debt is bad code, and not all bad code is technical debt.\nSometimes your bad code is just that: bad code. Calling it technical debt often feels like a more forgiving and friendly way of referring to what may have just been a poor implementation or a substandard piece of work.\nIt is an oft-misunderstood phrase, and when mistaken for meaning \u2018anything legacy or old hacky or nasty or bad\u2019, technical debt is swept under the carpet along with all of the other parts of the codebase we\u2019d rather not talk about, and therein lies the problem.\nWe need to talk about technical debt.\nWhat We Talk About When We Talk About Technical Debt\nThe thing that separates technical debt from the rest of the hacky code in our project is the fact that technical debt, by definition, is something that we knowingly and strategically entered into. Debt doesn\u2019t happen by accident: debt happens when we choose to gain something otherwise-unattainable immediately in return for paying it back (with interest) later on.\nAn Example\nYou\u2019re a front-end developer working on a SaaS product, and your sales team is courting a large customer \u2013 a customer so large that you can\u2019t really afford to lose them. The customer tells you that as long as you can allow them to theme your SaaS application according to their branding, they are willing to sign on the dotted line\u2026 the problem being that your CSS architecture was never designed to incorporate theming at all, and there isn\u2019t currently a nice, clean way to incorporate a theme into the codebase.\nYou and the business make the decision that you will hack a theme into the product in two days. It\u2019s going to be messy, it\u2019s going to be ugly, but you can\u2019t afford to lose a huge customer just because your CSS isn\u2019t quite right, right now. This is technical debt.\nYou deliver the theme, the customer signs up, and everyone is happy. Except you (and the business, because you are one and the same) have a decision to make:\n\nDo we go back and build theming into the CSS architecture as a first-class citizen, porting the hacked theme back into a codified and formal framework?\nDo we carry on as we are? Things are working okay, and the customer paid up, so is there any reason to invest time and effort into things after we (and the customer) got what we wanted?\n\nOption 1 is choosing to pay off your debts; Option 2 is ignoring your repayments.\nWith Option 1, you\u2019re acknowledging that you did what you could given the constraints, but, free of constraints, you\u2019d have done something different. Now, you are choosing to implement that something different.\nWith Option 2, however, you are avoiding your responsibility to repay your debt, and you are letting interest accrue. The problem here is that\u2026\n\nyour SaaS product now offers theming to one of your customers;\nanother potential customer might also demand the ability to theme their instance of your product;\nyou can\u2019t refuse them that request, nor can you quickly fulfil it;\nyou hack in another theme, thus adding to the balance of your existing debt;\nand so on (plus interest) for every subsequent theme you need to implement.\n\nHere you have increased entropy whilst making little to no attempt to address what you already knew to be problems.\nYour second, third, fourth, fifth request for theming will be hacked on top of your hack, further accumulating debt whilst offering nothing by way of a repayment. After a long enough period, the code involved will get so unwieldy, so hard to work with, that you are forced to tear it all down and start again, and the most painful part of this is that you\u2019re actually paying off even more than your debt repayments would have been in the first place. Two days of hacking plus, say, five days of subsequent refactoring, would still have been substantially less than the weeks you will now have to spend rewriting your CSS to fix and incorporate the themes properly. You\u2019ve made a loss; your strategic debt ultimately became a loss-making exercise.\nThe important thing to note here is that you didn\u2019t necessarily write bad code. You knew there were two options: the quick way and the correct way. The decision to take the quick route was a definite choice, because you knew there was a better way. Implementing the better way is your repayment.\nGood Debt and Bad Debt\nTechnical debt is acceptable as long as you have intentions to settle; it can be a valuable solution to a business problem, provided the right approach is taken afterwards. That doesn\u2019t, however, mean that all debt is born equal. Just as in real life, there is good debt and there is bad debt.\nGood debt might be\u2026\n\na mortgage;\na student loan, or;\na business loan.\n\nThese are types of debt that will secure you the means of repaying them. These are well considered debts whose very reason for being will allow you to make the money to pay them off\u2014they have real, tangible benefit.\nA business loan to secure some equipment and premises will allow you to start an enterprise whose revenue will allow you to pay that debt back; a student loan will allow you to secure the kind of job that has the ability to pay a student loan back.\nThese kinds of debt involve a considered and well-balanced decision to acquire something in the short term in the knowledge that you will have the means, in the long term, to pay it back.\nConversely, bad debt might be\u2026\n\nborrowing $1,000 from a loan shark so you can go to Vegas, or;\ntaking out a payday loan in order to buy a new television.\n\nBoth of these kinds of debt will leave you paying for things that didn\u2019t provide you a way of earning your own capital. That is to say, the loans taken did not secure anything that would help pay off said loans. These are bad debts that will usually provide a net loss. You really are only gaining the short term in exchange for a long term financial responsibility: i.e., was it worth it?\nA good litmus test for debt is to compare the gains of its immediate benefit with the cost of its long term commitment.\nThe earlier example of theming a site is a good debt, provided we are keeping up our repayments (all debt is bad debt if you don\u2019t). A calculated decision to do something \u2018wrong\u2019 in the short term with the promise of better payoffs later on.\nBad Technical Debt\nThe majority of my work is with front-end development teams\u2014CSS is what I do. To that end, the most succinct example of technical debt for that audience is simply:\n!important\nAll front-end developers know the horrors and dangers associated with using !important, yet we continue to use it. Why?\nIt\u2019s not necessarily because we\u2019re bad developers, but because we see a shortcut. !important is usually implemented as a quick way out of a sticky specificity situation. We could spend the rest of the day refactoring our CSS to fix the issue at its source, or we can spend mere seconds typing the word !important and patch over the symptoms.\nThis is us making an explicit decision to do something less than ideal now in exchange for immediate benefit. After all, refactoring our CSS will take a lot more time, and will still only leave us with the same outcome that the vastly quicker !important solution will, so it seems to make better business sense.\nHowever, this is a bad debt. !important takes seconds to implement but weeks to refactor. The cost of refactoring this back out later will be an order of magnitude higher than it would be to have done things properly the first time. The first !important usually sets a precedent, and subsequent developers are likely to have to use it themselves in order to get around the one that you left.\nSo many CSS projects deteriorate because of this one simple word, and rewrites become more and more imminent. That makes it possibly the most costly 10 bytes a CSS developer could ever write.\nBad Code\nNow we\u2019ve got a good idea of what constitutes technical debt, let\u2019s take a look at what constitutes bad code. Something I hear time and time again in my client work goes a little like this:\n\nWe\u2019ve amassed a lot of technical debt and we\u2019d like to get a strategy in place\nto begin dealing with it.\n\nWhilst I genuinely admire their willingness to identify and desire to fix problems in their code, sometimes they\u2019re not looking at technical debt at\nall\u2014sometimes they\u2019re just looking at bad code, plain and simple.\nWhere technical debt is knowing that there\u2019s a better way, but the quicker way makes more sense right now, bad code is not caring if there\u2019s a better way at all.\nAgain, looking at a CSS-specific world, a lot of bad code is contributed by non-front-end developers with little training, appreciation, or even respect for the front-end landscape. Writing code with reckless abandon should not be described as technical debt, because to do so would imply that\u2026\n\nthe developers knew they were implementing a sub-par solution, but\u2026\nthe developers also knew that a better solution was out there, which\u2026\nimplies that it can be tidied up relatively simply.\n\nDevelopers writing bad code is a larger and more cultural problem that requires a lot more effort to fix. Hopefully\u2014and usually\u2014bad code is in the minority, but it helps to be objective in identifying and solving it. Bad code usually doesn\u2019t happen for a good enough reason, and is therefore much harder to justify.\nTechnical debt often represents ability in judgement, whereas bad code often represents a gap in skills.\nTakeaway\nTake time to familiarise yourself with the true concepts underlying technical debt and why it exists. Understand that technical debt can be good or bad. Admit that sometimes code is just of poor quality.\nUnderstanding these points will allow you to make better calls around what you might need to refactor and when, and what skills gaps you might have in your team.\n\nSometimes it\u2019s okay to cut corners if there is a tangible gain to be had in the immediate term.\nTechnical debt is okay provided it is a sensible debt and you have intentions to pay it off.\nTechnical debt is not necessarily synonymous with bad code, and bad code isn\u2019t necessarily technical debt. Technical debt is code that was implemented given limited knowledge or resource, with the understanding that you would need to repay something in future.\nTechnical debt is not inherently bad\u2014failure to make repayments is. Periodically, it is justifiable\u2014encouraged, even\u2014to enter a debt in order to fulfil a more pressing matter. However, it is imperative that we begin making repayments as soon as we are capable, be that based on newly available time or knowledge.\nBad code is worse than technical debt as it represents a lack of knowledge or quality control within a team. It needs a much more fundamental fix.", "year": "2016", "author": "Harry Roberts", "author_slug": "harryroberts", "published": "2016-12-05T00:00:00+00:00", "url": "https://24ways.org/2016/we-need-to-talk-about-technical-debt/", "topic": "code"}
{"rowid": 305, "title": "CSS Writing Modes", "contents": "Since you may not have a lot of time, I\u2019m going to start at the end, with the dessert.\nYou can use a little-known, yet important and powerful CSS property to make text run vertically. Like this.\n\nOr instead of running text vertically, you can layout a set of icons or interface buttons in this way. Or, of course, with anything on your page.  \nThe CSS I\u2019ve applied makes the browser rethink the orientation of the world, and flow the layout of this element at a 90\u00b0 angle to \u201cnormal\u201d. Check out the live demo, highlight the headline, and see how the cursor is now sideways.\nSee the Pen Writing Mode Demo \u2014 Headline by Jen Simmons (@jensimmons) on CodePen.\n\nThe code for accomplishing this is pretty simple. \nh1 { \n  writing-mode: vertical-rl;\n}\nThat\u2019s all it takes to switch the writing mode from the web\u2019s default horizontal top-to-bottom mode to a vertical right-to-left mode. If you apply such code to the html element, the entire page is switched, affecting the scroll direction, too. \nIn my example above, I\u2019m telling the browser that only the h1 will be in this vertical-rl mode, while the rest of my page stays in the default of horizontal-tb.\nSo now the dessert course is over. Let me serve up this whole meal, and explain the the CSS Writing Mode Specification.\nWhy learn about writing modes?\nThere are three reasons I\u2019m teaching writing modes to everyone\u2014including western audiences\u2014and explaining the whole system, instead of quickly showing you a simple trick.\n\n\nWe live in a big, diverse world, and learning about other languages is fascinating. Many of you lay out pages in languages like Chinese, Japanese and Korean. Or you might be inspired to in the future.\n\n\nUsing writing-mode to turn bits sideways is cool. This CSS can be used in all kinds of creative ways, even if you are working only in English.\n\nMost importantly, I\u2019ve found understanding Writing Modes incredibly helpful when understanding Flexbox and CSS Grid. Before I learned Writing Mode, I felt like there was still a big hole in my knowledge, something I just didn\u2019t get about why Grid and Flexbox work the way they do. Once I wrapped my head around Writing Modes, Grid and Flexbox got a lot easier. Suddenly the Alignment properties, align-* and justify-*, made sense.\n\nWhether you know about it or not, the writing mode is the first building block of every layout we create. You can do what we\u2019ve been doing for 25 years \u2013 and leave your page set to the default left-to-right direction, horizontal top-to-bottom writing mode. Or you can enter a world of new possibilities where content flows in other directions.\nCSS properties\nI\u2019m going to focus on the CSS writing-mode property in this article. It has five possible options:\n  writing-mode: horizontal-tb;\n  writing-mode: vertical-rl;\n  writing-mode: vertical-lr;\n  writing-mode: sideways-rl;\n  writing-mode: sideways-lr;\nThe CSS Writing Modes Specification is designed to support a wide range of written languages in all our human and linguistic complexity. Which\u2014spoiler alert\u2014is pretty insanely complex. The global evolution of written languages has been anything but simple. \nSo I\u2019ve got to start with explaining some basic concepts of web page layout and writing systems. Then I can show you what these CSS properties do. \nInline Direction, Block Direction, and Character Direction\nIn the world of the web, there\u2019s a concept of \u2018block\u2019 and \u2018inline\u2019 layout. If you\u2019ve ever written display: block or display: inline, you\u2019ve leaned on these concepts.  \nIn the default writing mode, blocks stack vertically starting at the top of the page and working their way down. Think of how a bunch of block-levels elements stack\u2014like a bunch of a paragraphs\u2014that\u2019s the block direction. \n\nInline is how each line of text flows. The default on the web is from left to right, in horizontal lines. Imagine this text that you are reading right now, being typed out one character at a time on a typewriter. That\u2019s the inline direction. \n\nThe character direction is which way the characters point. If you type a capital \u201cA\u201d for instance, on which side is the top of the letter? Different languages can point in different directions. Most languages have their characters pointing towards the top of the page, but not all.\n\nPut all three together, and you start to see how they work as a system. \nThe default settings for the web work like this.\nNow that we know what block, inline, and character directions mean, let\u2019s see how they are used in different writing systems from around the world.\nThe four writing systems of CSS Writing Modes\nThe CSS Writing Modes Specification handles all the use cases for four major writing systems; Latin, Arabic, Han and Mongolian. \nLatin-based systems\nOne writing system dominates the world more than any other, reportedly covering about 70% of the world\u2019s population. \n\nThe text is horizontal, running from left to right, or LTR. The block direction runs from top to bottom. \nIt\u2019s called the Latin-based system because it includes all languages that use the Latin alphabet, including English, Spanish, German, French, and many others. But there are many non-Latin-alphabet languages that also use this system, including Greek, Cyrillic (Russian, Ukrainian, Bulgarian, Serbian, etc.), and Brahmic scripts (Devanagari, Thai, Tibetan), and many more.\nYou don\u2019t need to do anything in your CSS to trigger this mode. This is the default. \nBest practices, however, dictate that you declare in your opening <html> element which language and which direction (LTR or RTL) you are using. This website, for instance, uses <html lang='en-gb' dir='ltr'> to let the browser know this content is published in Great Britian\u2019s version of English, in a left to right direction. \nArabic-based systems\nArabic, Hebrew and a few other languages run the inline direction from right to left. This is commonly known as RTL.  \nNote that the inline direction still runs horizontally. The block direction runs from top to bottom. And the characters are upright.\n\nIt\u2019s not just the flow of text that runs from right to left, but everything about the layout of the website. The upper right-hand corner is the starting position. Important things are on the right. The eyes travel from right to left. So, typically RTL websites use layouts that are just like LTR websites, only flipped.\nOn websites that support both LTR and RTL, like the United Nations\u2019 site at un.org, the two layouts are mirror images of each other.\nFor many web developers, our experiences with internationalization have focused solely on supporting Arabic and Hebrew script. \nCSS layout hacks for internationalization & RTL\nTo prepare an LTR project to support RTL, developers have had to create all sorts of hacks. For example, the Drupal community started a convention of marking every margin-left and -right, every padding-left and -right, every float: left and float: right with the comment /* LTR */. Then later developers could search for each instance of that exact comment, and create stylesheets to override each left with right, and vice versa. It\u2019s a tedious and error prone way to work. CSS itself needed a better way to let web developers write their layout code once, and easily switch language directions with a single command.\nOur new CSS layout system does exactly that. Flexbox, Grid and Alignment use start and end instead of left and right. This lets us define everything in relationship to the writing system, and switch directions easily. By writing justify-content: flex-start, justify-items: end, and eventually margin-inline-start: 1rem we have code that doesn\u2019t need to be changed. \nThis is a much better way to work. I know it can be confusing to think through start and end as replacements for left and right. But it\u2019s better for any multiligual project, and it\u2019s better for the web as a whole.\nSadly, I\u2019ve seen CSS preprocessor tools that claim to \u201cfix\u201d the new CSS layout system by getting rid of start and end and bringing back left and right. They want you to use their tool, write justify-content: left, and feel self-righteous. It seems some folks think the new way of working is broken and should be discarded. It was created, however, to fulfill real needs. And to reflect a global internet. As Bruce Lawson says, WWW stands for the World Wide Web, not the Wealthy Western Web. Please don\u2019t try to convince the industry that there\u2019s something wrong with no longer being biased towards western culture. Instead, spread the word about why this new system is here.  \nSpend a bit of time drilling the concept of inline and block into your head, and getting used to start and end. It will be second nature soon enough. \nI\u2019ve also seen CSS preprocessors that let us use this new way of thinking today, even as all the parts aren\u2019t fully supported by browsers yet. Some tools let you write text-align: start instead of text-align: left, and let the preprocessor handle things for you. That is terrific, in my opinion. A great use of the power of a preprocessor to help us switch over now. \nBut let\u2019s get back to RTL. \nHow to declare your direction\nYou don\u2019t want to use CSS to tell the browser to switch from an LTR language to RTL. You want to do this in your HTML. That way the browser has the information it needs to display the document even if the CSS doesn\u2019t load.\nThis is accomplished mainly on the html element. You should also declare your main language. As I mentioned above, the 24 ways website is using <html lang='en-gb' dir='ltr'> to declare the LTR direction and the use of British English. The UN Arabic website uses <html lang='ar' dir='rtl'>to declare the site as an Arabic site, using a RTL layout. \nThings get more complicated when you\u2019ve got a page with a mix of languages. But I\u2019m not going to get into all of that, since this article is focused on CSS and layouts, not explaining everything about internationalization. \nLet me just leave direction here by noting that much of the heavy work of laying out the characters which make up each word is handled by Unicode. If you are interested in learning more about LTR, RTL and bidirectional text, watch this video: Introduction to Bidirectional Text, a presentation by Elika Etemad. \nMeanwhile, let\u2019s get back to CSS.\nThe writing mode CSS for Latin-based and Arabic-based systems\nFor both of these systems\u2014Latin-based and Arabic-based, whether LTR or RTL\u2014the same CSS property applies for specifying the writing mode: writing-mode: horizontal-tb. That\u2019s because in both systems, the inline text flow is horizontal, while the block direction is top-to-bottom. This is expressed as horizontal-tb.\nhorizontal-tb is the default writing mode for the web, so you don\u2019t need to specify it unless you are overriding something else higher up in the cascade. You can just imagine that every site you\u2019ve ever built came with:\nhtml {\n  writing-mode: horizontal-tb;\n}\nNow let\u2019s turn our attention to the vertical writing systems. \nHan-based systems\nThis is where things start to get interesting. \nHan-based writing systems include CJK languages, Chinese, Japanese, Korean and others. There are two options for laying out a page, and sometimes both are used at the same time.\nMuch of CJK text is laid out like Latin-based languages, with a horizontal top-to-bottom block direction, and a left-to-right inline direction. This is the more modern way to doing things, started in the 20th century in many places, and further pushed into domination by the computer and later the web. \nThe CSS to do this bit of the layouts is the same as above:\nsection {\n  writing-mode: horizontal-tb;\n}\nOr, you know, do nothing, and get that result as a default. \nAlternatively Han-based languages can be laid out in a vertical writing mode, where the inline direction runs vertically, and the block direction goes from right to left. \nSee both options in this diagram:\n\nNote that the horizontal text flows from left to right, while the vertical text flows from right to left. Wild, eh? \nThis Japanese issue of Vogue magazine is using a mix of writing modes. The cover opens on the left spine, opposite of what an English magazine does.  \n\nThis page mixes English and Japanese, and typesets the Japanese text in both horizontal and vertical modes. Under the title \u201cRichard Stark\u201d in red, you can see a passage that\u2019s horizontal-tb and LTR, while the longer passage of text at the bottom of the page is typeset vertical-rl. The red enlarged cap marks the beginning of that passage. The long headline above the vertical text is typeset LTR, horizontal-tb.\n\nThe details of how to set the default of the whole page will depend on your use case. But each element, each headline, each section, each article can be marked to flow the opposite of the default however you\u2019d like.\nFor example, perhaps you leave the default as horizontal-tb, and specify your vertical elements like this:\ndiv.articletext {\n  writing-mode: vertical-rl;\n}\nOr alternatively you could change the default for the page to a vertical orientation, and then set specific elements to horizontal-tb, like this:\nhtml { \n  writing-mode: vertical-rl;\n}\nh2, .photocaptions, section {\n  writing-mode: horizontal-tb;\n}\nIf your page has a sideways scroll, then the writing mode will determine whether the page loads with upper left corner as the starting point, and scroll to the right (horizontal-tb as we are used to), or if the page loads with the upper right corner as the starting point, scrolling to the left to display overflow. Here\u2019s an example of that change in scrolling direction, in a CSS Writing Mode demo by Chen Hui Jing. Check out her demo \u2014 you can switch from horizontal to vertical writing modes with a checkbox and see the difference. \n\nMongolian-based systems\nNow, hopefully so far all of this kind of makes sense. It might be a bit more complicated than expected, but it\u2019s not so hard. Well, enter the Mongolian-based systems.\nMongolian is also a vertical script language. Text runs vertically down the page. Just like Han-based systems. There are two major differences. First, the block direction runs the other way. In Mongolian, block-level elements stack from left to right. \nHere\u2019s a drawing of how Wikipedia would look in Mongolian if it were laid out correctly.\nPerhaps the Mongolian version of Wikipedia will be redone with this layout.\nNow you might think, that doesn\u2019t look so weird. Tilt your head to the left, and it\u2019s very familiar. The block direction starts on the left side of the screen and goes to the right. The inline direction starts on the top of the page and moves to the bottom (similar to RTL text, just turned 90\u00b0 counter-clockwise). But here comes the other huge difference. The character direction is \u201cupside down\u201d. The top of the Mongolian characters are not pointing to the left, towards the start edge of the block direction. They point to the right. Like this:\n\nNow you might be tempted to ignore all this. Perhaps you don\u2019t expect to be typesetting Mongolian content anytime soon. But here\u2019s why this is important for everyone \u2014 the way Mongolian works defines the results writing-mode: vertical-lr. And it means we cannot use vertical-lr for typesetting content in other languages in the way we might otherwise expect. \nIf we took what we know about vertical-rl and guessed how vertical-lr works, we might imagine this:\n\nBut that\u2019s wrong. Here\u2019s how they actually compare:\n\nSee the unexpected situation? In both writing-mode: vertical-rl and writing-mode: vertical-lr latin text is rotated clockwise. Neither writing mode let\u2019s us rotate text counter-clockwise. \nIf you are typesetting Mongolian content, apply this CSS in the same way you would apply writing-mode to Han-based writing systems. To the whole page on the html element, or to specific pages of the page like this:\nsection {\n  writing-mode: vertical-lr;\n}\nNow, if you are using writing-mode for a graphic design effect on a language that is otherwise typesets horizontally, I don\u2019t think writing-mode: vertical-lr is useful. If the text wraps onto two lines, it stacks in a very unexpected way. So I\u2019ve sort of obliterated it from my toolkit. I find myself using writing-mode: vertical-rl a lot. And never using -lr. Hm.\nWriting modes for graphic design\nSo how do we use writing-mode to turn English headlines sideways? We could rely on transform: rotate()\nHere are two examples, one for each direction. (By the way, each of these demos use CSS Grid for their overall layout, so be sure to test them in a browser that supports CSS Grid, like Firefox Nightly.)\n\nIn this demo 4A, the text is rotated clockwise using this code: \nh1 {\n  writing-mode: vertical-rl;\n}\n\nIn this demo 4B, the text is rotated counter-clockwise using this code: \nh1 {\n  writing-mode: vertical-rl;\n  transform: rotate(180deg);\n  text-align: right;\n}\nI use vertical-rl to rotate the text so that it takes up the proper amount of space in the overall flow of the layout. Then I rotate it 180\u00b0 to spin it around to the other direction. And then I use text-align: right to get it to rise up to the top of it\u2019s container. This feels like a hack, but it\u2019s a hack that works.\nNow what I would like to do instead is use another CSS value that was designed for this use case \u2014 one of the two other options for writing mode.\nIf I could, I would lay out example 4A with:\nh1 {\n  writing-mode: sideways-rl;\n}\nAnd layout example 4B with: \nh1 {\n  writing-mode: sideways-lr;\n}\nThe problem is that these two values are only supported in Firefox. None of the other browsers recognize sideways-*. Which means we can\u2019t really use it yet. \nIn general, the writing-mode property is very well supported across browsers. So I\u2019ll use writing-mode: vertical-rl for now, with the transform: rotate(180deg); hack to fake the other direction. \nThere\u2019s much more to what we can do with the CSS designed to support multiple languages, but I\u2019m going to stop with this intermediate introduction. \nIf you do want a bit more of a taste, look at this example that adds text-orientation: upright; to the mix \u2014 turning the individual letters of the latin font to be upright instead of sideways.\n\nIt\u2019s this demo 4C, with this CSS applied: \nh1 {\n  writing-mode: vertical-rl;\n  text-orientation: upright;\n  text-transform: uppercase;\n  letter-spacing: -25px;\n}\nYou can check out all my Writing Modes demos at labs.jensimmons.com/#writing-modes. \n\nI\u2019ll leave you with this last demo. One that applies a vertical writing mode to the sub headlines of a long article. I like how small details like this can really bring a fresh feeling to the content. \nSee the Pen Writing Mode Demo \u2014 Article Subheadlines by Jen Simmons (@jensimmons) on CodePen.", "year": "2016", "author": "Jen Simmons", "author_slug": "jensimmons", "published": "2016-12-23T00:00:00+00:00", "url": "https://24ways.org/2016/css-writing-modes/", "topic": "code"}
{"rowid": 306, "title": "What next for CSS Grid Layout?", "contents": "In 2012 I wrote an article for 24 ways detailing a new CSS Specification that had caught my eye, at the time with an implementation only in Internet Explorer. What I didn\u2019t realise at the time was that CSS Grid Layout was to become a theme on which I would base the next four years of research, experimentation, writing and speaking. \nAs I write this article in December 2016, we are looking forward to CSS Grid Layout being shipped in Chrome and Firefox. What will ship early next year in those browsers is expanded and improved from the early implementation I explored in 2012. Over the last four years the spec has been developed as part of the CSS Working Group process, and has had input from browser engineers, specification writers and web developers. Use cases have been discussed, and features added.\nThe CSS Grid Layout specification is now a Candidate Recommendation. This status means the spec is to all intents and purposes, finished. The discussions now happening are on fine implementation details, and not new feature ideas. It makes sense to draw a line under a specification in order that browser vendors can ship complete, interoperable implementations. That approach is good for all of us, it makes development far easier if we know that a browser supports all of the features of a specification, rather than working out which bits are supported. However it doesn\u2019t mean that works stops here, and that new use cases and features can\u2019t be proposed for future levels of Grid Layout. Therefore, in this article I\u2019m going to take a look at some of the things I think grid layout could do in the future. I would love for these thoughts to prompt you to think about how Grid - or any CSS specification - could better suit the use cases you have.\nSubgrid - the missing feature of Level 1\nThe implementation of CSS Grid Layout in Chrome, Firefox and Webkit is comparable and very feature complete. There is however one standout feature that has not been implemented in any browser as yet - subgrid. Once you set the value of the display property to grid, any direct children of that element become grid items. This is similar to the way that flexbox behaves, set display: flex and all direct children become flex items. The behaviour does not apply to children of those items. You can nest grids, just as you can nest flex containers, but the child grids have no relationship to the parent.\n\nNesting Grids by Rachel Andrew (@rachelandrew) on CodePen.\nThe subgrid behaviour would enable the grid defined on the parent to be used by the children. I feel this would be most useful when working with a multiple column flexible grid - for example a typical 12 column grid. I could define a grid on a wrapper, then position UI elements on that grid - from the major structural elements of my page down through the child elements to a form where I wanted the field to line up with items above.\nThe specification contained an initial description of subgrid, with a value of subgrid for grid-template-columns and grid-template-rows, you can read about this in the August 2015 Working Draft. This version of the specification would have meant you could declare a subgrid in one dimension only, and create a different set of tracks in the other.\nIn an attempt to get some implementation of subgrid, a revised specification was proposed earlier this year. This gives a single subgrid value of the display property. As we now cannot specify a subgrid on rows OR columns this limits us to have a subgrid that works in two dimensions. At this point neither version has been implemented by anyone, and subgrids are marked as \u201cat risk\u201d in the Level 1 Candidate Recommendation. With regard to \u2018at-risk\u2019 this is explained as follows:\n\n\u201c\u2018At-risk\u2019 is a W3C Process term-of-art, and does not necessarily imply that the feature is in danger of being dropped or delayed. It means that the WG believes the feature may have difficulty being interoperably implemented in a timely manner, and marking it as such allows the WG to drop the feature if necessary when transitioning to the Proposed Rec stage, without having to publish a new Candidate Rec without the feature first.\u201d \n\nIf we lose subgrid from Level 1, as it looks likely that we will, this does give us a chance to further discuss and iterate on that feature. My current thoughts are that I\u2019m not completely happy about subgrids being tied to both dimensions and feel that a return to the earlier version, or something like it, would be preferable. \nFurther reading about subgrid\n\nMy post from 2015 detailing why I feel subgrid is important\nMy post based on the revised specification\nEric Meyer\u2019s thoughts on subgrid\nWrite-up of a discussion from Igalia who work on the Blink and Webkit browser implementations\n\nStyling cells, tracks and areas\nHaving defined a grid with CSS Grid Layout you can place child elements into that grid, however what you can\u2019t do is style the grid tracks or cells. Grid doesn\u2019t even go as far as multiple column layout, which has the column-rule properties.\nIn order to set a background colour on a grid cell at the moment you would have to add an empty HTML element or insert some generated content as in the below example. I\u2019m using a 1 pixel grid gap to fake lines between grid cells, and empty div elements, and some generated content to colour those cells.\n\nFaked backgrounds and borders by Rachel Andrew (@rachelandrew) on CodePen.\nI think it would be a nice addition to Grid Layout to be able to directly add backgrounds and borders to cells, tracks and areas. There is an Issue raised in the CSS WG Drafts repository for Decorative Grid Cell pseudo-elements, if you want to add thoughts to that.\nMore control over auto placement\nIf you haven\u2019t explicitly placed the direct children of your grid element they will be laid out according to the grid auto placement rules. You can see in this example how we have created a grid and the items are placing themselves into cells on that grid.\n\nItems auto-place on a defined grid by Rachel Andrew (@rachelandrew) on CodePen.\nThe auto-placement algorithm is very cool. We can position some items, leaving others to auto-place; we can set items to span more than one track; we can use the grid-auto-flow property with a value of dense to backfill gaps in our grid.\n\nWebsafe colors meet CSS Grid (auto-placement demo) by Rachel Andrew (@rachelandrew) on CodePen.\nI think however this could be taken further. In this issue posted to my CSS Grid AMA on GitHub, the question is raised as to whether it would be possible to ask grid to place items on the next available line of a certain name. This would allow you to skip tracks in the grid when using auto-placement, an issue that has also been raised by Emil Bj\u00f6rklund in this post to the www-style list prior to spec discussion moving to Github. I think there are probably similar issues, if you can think of one add a comment here.\nCreating non-rectangular grid areas\nA grid area is a collection of grid cells, defined by setting the start and end lines for columns and rows or by creating the area in the value of the grid-template-areas property as shown below. Those areas however must be rectangular - you can\u2019t create an L-shaped or otherwise non-regular shape.\n\nGrid Areas by Rachel Andrew (@rachelandrew) on CodePen.\n\nPerhaps in the future we could define an L-shape or other non-rectangular area into which content could flow, as in the below currently invalid code where a quote is embedded into an L-shaped content area.\n.wrapper {\n  display: grid;\n  grid-template-areas:\n      \"sidebar header  header\"\n      \"sidebar content quote\"\n      \"sidebar content content\";\n}\nFlowing content through grid cells or areas\nSome uses cases I have seen perhaps are not best solved by grid layout at all, but would involve grid working alongside other CSS specifications. As I detail in this post, there are a class of problems that I believe could be solved with the CSS Regions specification, or a revised version of that spec.\nBeing able to create a grid layout, then flow content through the areas could be very useful. Jen Simmons presented to the CSS Working Group at the Lisbon meeting a suggestion as to how this might work.\nIn a post from earlier this year I looked at a collection of ideas from specifications that include Grid, Regions and Exclusions. These working notes from my own explorations might prompt ideas of your own.\nSolving the keyboard/layout disconnect\nOne issue that grid, and flexbox to a lesser extent, raises is that it is very easy to end up with a layout that is disconnected from the underlying markup. This raises problems for people navigating using the keyboard as when tabbing around the document you find yourself jumping to unexpected places. The problem is explained by L\u00e9onie Watson with reference to flexbox in Flexbox and the keyboard navigation disconnect.\nThe grid layout specification currently warns against creating such a disconnect, however I think it will take careful work by web developers in order to prevent this. It\u2019s also not always as straightforward as it seems. In some cases you want the logical order to follow the source, and others it would make more sense to follow the visual. People are thinking about this issue, as you can read in this mailing list discussion.\nBringing your ideas to the future of Grid Layout\nWhen I\u2019m not getting excited about new CSS features, my day job involves working on a software product - the CMS that is serving this very website, Perch. When we launched Perch there were many use cases that we had never thought of, despite having a good idea of what might be needed in a CMS and thinking through lots of use cases. The additional use cases brought to our attention by our customers and potential customers informed the development of the product from launch. The same will be true for Grid Layout.\nAs a \u201cproduct\u201d grid has been well thought through by many people. Yet however hard we try there will be use cases we just didn\u2019t think of. You may well have one in mind right now. That\u2019s ok, because as with any CSS specification, once Level One of grid  is complete, work can begin on Level Two. The feature set of Level Two will be informed by the use cases that emerge as people get to grips with what we have now.\nThis is where you get to contribute to the future of layout on the web. When you hit up against the things you cannot do, don\u2019t just mutter about how the CSS Working Group don\u2019t listen to regular developers and code around the problem. Instead, take a few minutes and write up your use case. Post it to your blog, to Medium, create a CodePen and go to the CSS Working Group GitHub specs repository and post an issue there. Write some pseudo-code, draw a picture, just make sure that the use case is described in enough detail that someone can see what problem you want grid to solve. It may be that - as with any software development - your use case can\u2019t be solved in exactly the way you suggest. However once we have a use case, collected with other use cases, methods of addressing that class of problems can be investigated. \nI opened this article by explaining I\u2019d written about grid layout four years ago, and how we\u2019re only now at a point where we will have Grid Layout available in the majority of browsers. Specification development, and implementation into browsers takes time. This is actually a good thing, as it\u2019s impossible to take back CSS once it is out there and being used by production websites. We want CSS in the wild to be well thought through and that takes time. So don\u2019t feel that because you don\u2019t see your use case added to a spec immediately it has been ignored. Do your future self a favour and write down your frustrations or thoughts, and we can all make sure that the web platform serves the use cases we\u2019re dealing with now and in the future.", "year": "2016", "author": "Rachel Andrew", "author_slug": "rachelandrew", "published": "2016-12-12T00:00:00+00:00", "url": "https://24ways.org/2016/what-next-for-css-grid-layout/", "topic": "code"}
{"rowid": 307, "title": "Get the Balance Right: Responsive Display Text", "contents": "Last year in 24 ways I urged you to Get Expressive with Your Typography. I made the case for grabbing your readers\u2019 attention by setting text at display sizes, that is to say big. You should consider very large text in the same way you might a hero image: a picture that creates an atmosphere and anchors your layout.\nWhen setting text to be read, it is best practice to choose body and subheading sizes from a pre-defined scale appropriate to the viewport dimensions. We set those sizes using rems, locking the text sizes together so they all scale according to the page default and your reader\u2019s preferences.  You can take the same approach with display text by choosing larger sizes from the same scale.\nHowever, display text, as defined by its purpose and relative size, is text to be seen first, and read second. In other words a picture of text. When it comes to pictures, you are likely to scale all scene-setting imagery - cover photos, hero images, and so on - relative to the viewport. Take the same approach with display text: lock the size and shape of the text to the screen or browser window.\nIntroducing viewport units\nWith CSS3 came a new set of units which are locked to the viewport. You can use these viewport units wherever you might otherwise use any other unit of length such as pixels, ems or percentage. There are four viewport units, and in each case a value of 1 is equal to 1% of either the viewport width or height as reported in reference1 pixels:\n\nvw - viewport width,\nvh - viewport height,\nvmin - viewport height or width, whichever is smaller\nvmax - viewport height or width, whichever is larger\n\nIn one fell swoop you can set the size of a display heading to be proportional to the screen or browser width, rather than choosing from a scale in a series of media queries. The following makes the heading font size 13% of the viewport width:\nh1 {\n    font-size: 13 vw;\n}\nSo for a selection of widths, the rendered font size would be:\nRendered font size (px)\nViewport width\n13\u202fvw\n320\n42\n768\n100\n1024\n133\n1280\n166\n1920\n250\n\nA problem with using vw in this manner is the difference in text block proportions between portrait and landscape devices. Because the font size is based on the viewport width, the text on a landscape display is far bigger than when rendered on the same device held in a portrait orientation. \nLandscape text is much bigger than portrait text when using vw units.\nThe proportions of the display text relative to the screen are so dissimilar that each orientation has its own different character, losing the inconsistency and considered design you would want when designing to make an impression.\nHowever if the text was the same size in both orientations, the visual effect would be much more consistent. This where vmin comes into its own. Set the font size using vmin and the size is now set as a proportion of the smallest side of the viewport, giving you a far more consistent rendering.\nh1 {\n    font-size: 13vmin;\n}\nLandscape text is consistent with portrait text when using vmin units.\nComparing vw and vmin renderings for various common screen dimensions, you can see how using vmin keeps the text size down to a usable magnitude:\nRendered font size (px)\nViewport\n13\u202fvw\n13\u202fvmin\n320 \u00d7 480\n42\n42\n414 \u00d7 736\n54\n54\n768 \u00d7 1024\n100\n100\n1024 \u00d7 768\n133\n100\n1280 \u00d7 720\n166\n94\n1366 \u00d7 768\n178\n100\n1440 \u00d7 900\n187\n117\n1680 \u00d7 1050\n218\n137\n1920 \u00d7 1080\n250\n140\n2560 \u00d7 1440\n333\n187\n\nHybrid font sizing\nUsing vertical media queries to set text in direct proportion to screen dimensions works well when sizing display text. In can be less desirable when sizing supporting text such as sub-headings, which you may not want to scale upwards at the same rate as the display text. For example, we can size a subheading using vmin so that it starts at 16 px on smaller screens and scales up in the same way as the main heading:\nh1 {\n    font-size: 13vmin;\n}\nh2 {\n    font-size: 5vmin;\n}\nUsing vmin alone for supporting text can scale it too quickly\nThe balance of display text to supporting text on the phone works well, but the subheading text on the tablet, even though it has been increased in line with the main heading, is starting to feel disproportionately large and a little clumsy. This problem becomes magnified on even bigger screens.\nA solution to this is use a hybrid method of sizing text2. We can use the CSS calc() function to calculate a font size simultaneously based on both rems and viewport units. For example:\nh2 {\n    font-size: calc(0.5rem + 2.5vmin);\n}\nFor a 320 px wide screen, the font size will be 16 px, calculated as follows:\n(0.5 \u00d7 16) + (320 \u00d7 0.025) = 8 + 8 = 16px\nFor a 768 px wide screen, the font size will be 27 px:\n(0.5 \u00d7 16) + (768 \u00d7 0.025) = 8 + 19 = 27px\nThis results in a more balanced subheading that doesn\u2019t take emphasis away from the main heading:\n\nTo give you an idea of the effect of using a hybrid approach, here\u2019s a side-by-side comparison of hybrid and viewport text sizing:\ntable.ex--scale{width:100%;overflow: hidden;} table.ex--scale td{vertical-align:baseline;text-align:center;padding:0} tr.ex--scale-key{color:#666} tr.ex--scale-key td{font-size:.875rem;padding:0 0.125em} .ex--scale-2 tr.ex--scale-size{color:#ccc} tr.ex--scale-size td{font-size:1em;line-height:.34em;padding-bottom:.5rem} td.ex--scale-step{color:#000} td.ex--scale-hilite{color:red} .ex--scale-3 tr.ex--scale-size td{line-height:.9em}\n\ntop: calc() hybrid method; bottom: vmin only\n16\n20\n27\n32\n35\n40\n44\n16\n24\n38\n48\n54\n64\n72\n320\n480\n768\n960\n1080\n1280\n1440\n\nOver this festive period, try experiment with the proportion of rem and vmin in your hybrid calculation to see what feels best for your particular setting.\n\n\n\n\nA reference pixel is based on the logical resolution of a device which takes into account double density screens such as Retina displays.\u00a0\u21a9\ufe0e\n\n\nFor even more sophisticated uses of hybrid text sizing see the work of Mike Riethmuller.\u00a0\u21a9\ufe0e", "year": "2016", "author": "Richard Rutter", "author_slug": "richardrutter", "published": "2016-12-09T00:00:00+00:00", "url": "https://24ways.org/2016/responsive-display-text/", "topic": "code"}
{"rowid": 308, "title": "How to Make a Chrome Extension to Delight (or Troll) Your Friends", "contents": "If you\u2019re like me, you grew up drawing mustaches on celebrities. Every photograph was subject to your doodling wrath, and your brilliance was taken to a whole new level with computer programs like Microsoft Paint. The advent of digital cameras meant that no one was safe from your handiwork, especially not your friends. And when you finally got your hands on Photoshop, you spent hours maniacally giggling at your artistic genius. \nBut today is different. You\u2019re a serious adult with important things to do and a reputation to uphold. You keep up with modern web techniques and trends, and have little time for fun other than a random Giphy on Slack\u2026 right? \nNope. \nIf there\u2019s one thing 2016 has taught me, it\u2019s that we\u2014the self-serious, world-changing tech movers and shakers of the universe\u2014haven\u2019t changed one bit from our younger, more delightable selves.\nHow do I know? This year I created a Chrome extension called Tabby Cat and watched hundreds of thousands of people ditch productivity for randomly generated cats. Tabby Cat replaces your new tab page with an SVG cat featuring a silly name like \u201cStinky Dinosaur\u201d or \u201cTiny Potato\u201d. Over time, the cats collect goodies that vary in absurdity from fishbones to lawn flamingos to Raybans. Kids and adults alike use this extension, and analytics show the majority of use happens Monday through Friday from 9-5. The popularity of Tabby Cat has convinced me there\u2019s still plenty of room in our big, grown-up hearts for fun.\n\n\nToday, we\u2019re going to combine the formula behind Tabby Cat with your intrinsic desire to delight (or troll) your friends, and create a web app that generates your friends with random objects and environments of your choosing. You can publish it as a Chrome extension to replace your new tab, or simply host it as a website and point to it with the New Tab Redirect extension. \nHere\u2019s a sneak peek at my final result featuring my partner, my cat, and I in cheerfully weird accessories. Your result will look however you want it to.\n\nAlong the way, we\u2019ll cover how to build a Chrome extension that replaces the new tab page, and explore ways to program randomness into your work to create something truly delightful. \nWhat you\u2019ll need\n\nAdobe Illustrator (or a similar illustration program to export PNG)\nSome images of your friends\nA text editor\n\nNote: This can be as simple or as complex as you want it to be. Most of the application is pre-built so you can focus on kicking back and getting in touch with your creative side. If you want to dive in deeper, you\u2019ll find ways to do it.\nGetting started\n\nDownload a local copy of the boilerplate for today\u2019s tutorial here, and open it in a text editor. Inside, you\u2019ll find a simple web app that you can run in Chrome. \nOpen index.html in Chrome. You should see a grey page that says \u201cNoname\u201d.\nOpen template.pdf in Adobe Illustrator or a similar program that can export PNG. The file contains an artboard measuring 800px x 800px, with a dotted blue outline of a face. This is your template.\n\nNote: We\u2019re using Google Chrome to build and preview this application because the end-result is a Chrome extension. This means that the application isn\u2019t totally cross-browser compatible, but that\u2019s okay.\nStep 1: Gather your friends\nThe first thing to do is choose who your muses are. Since the holidays are upon us, I\u2019d suggest finding inspiration in your family.\nCreate your artwork\nFor each person, find an image where their face is pointed as forward as possible. Place the image onto the Artwork layer of the Illustrator file, and line up their face with the template. Then, rename the artboard something descriptive like face_bob. Here\u2019s my crew:\nAs you can see, my use of the word \u201cfamily\u201d extends to cats. There\u2019s no judgement here.\nNotice that some of my photos don\u2019t completely fill the artboard\u2013that\u2019s fine. The images will be clipped into ovals when they\u2019re rendered in the application.\nNow, export your images by following these steps:\n\nTurn the Template layer off and export the images as PNGs. \nIn the Export dialog, tick the \u201cUse Artboards\u201d checkbox and enter the range with your faces. \nExport at 72ppi to keep things running fast. \nSave your images into the images/ folder in your project.\n\nAdd your images to config.js\nOpen scripts/config.js. This is where you configure your extension. \nAdd key value pairs to the faces object. The key should be the person\u2019s name, and the value should be the filepath to the image.\nfaces: {\n    leslie: 'images/face_leslie.png',\n    kyle: 'images/face_kyle.png',\n    beep: 'images/face_beep.png'\n}\nThe application will choose one of these options at random each time you open a new tab. This pattern is used for everything in the config file. You give the application groups of choices, and it chooses one at random each time it loads. The only thing that\u2019s special about the faces object is that person\u2019s name will also be displayed when their face is chosen.\nNow, when you refresh the project in Chrome, you should see one of your friends along with their name, like this:\n\nCongrats, you\u2019re off and running!\nStep 2: Add adjectives\nNow that you\u2019ve loaded your friends into the application, it\u2019s time to call them names. This step definitely yields the most laughs for the least amount of effort.\nAdd a list of adjectives into the prefixes array in config.js. To get the words flowing, I took inspiration from ways I might describe some of my relatives during a holiday gathering\u2026\nprefixes: [\n    'Loving',\n    'Drunk',\n    'Chatty',\n    'Merry',\n    'Creepy',\n    'Introspective',\n    'Cheerful',\n    'Awkward',\n    'Unrelatable',\n    'Hungry',\n    ...\n]\nWhen you refresh Chrome, you should see one of these words prefixed before your friend\u2019s name. Voila!\n\nStep 3: Choose your color palette\nReal talk: I\u2019m bad at choosing color palettes, so I have a trick up my sleeve that I want to share with you. If you\u2019ve been blessed with the gift of color aptitude, skip ahead.\nHow to choose colors\nTo create a color palette, I start by going to a Coolors.co, and I hit the spacebar until I find a palette that I like. We need a wide gamut of hues for our palette, so lock down colors you like and keep hitting the spacebar until you find a nice, full range. You can use as many or as few colors as you like.\nCopy these colors into your swatches in Adobe Illustrator. They\u2019ll be the base for any illustrations you create later.\nNow you need a set of background colors. Here\u2019s my trick to making these consistent with your illustration palette without completely blending in. Use the \u201cAdjust Palette\u201d tool in Coolors to dial up the brightness a few notches, and the saturation down just a tad to remove any neon effect. These will be your background colors.\n\nAdd your background colors to config.js\nCopy your hex codes into the bgColors array in config.js.\nbgColors: [\n    '#FFDD77',\n    '#FF8E72',\n    '#ED5E84',\n    '#4CE0B3',\n    '#9893DA',\n    ...\n]\nNow when you go back to Chrome and refresh the page, you\u2019ll see your new palette!\n\nStep 4: Accessorize\nThis is the fun part. We\u2019re going to illustrate objects, accessories, lizards\u2014whatever you want\u2014and layer them on top of your friends.\nYour objects will be categorized into groups, and one option from each group will be randomly chosen each time you load the page. Think of a group like \u201chats\u201d or \u201cglasses\u201d. This will allow combinations of accessories to show at once, without showing two of the same type on the same person.\nCreate a group of accessories\nTo get started, open up Illustrator and create a new artboard out of the template. Think of a group of objects that you can riff on. I found hats to be a good place to start. If you don\u2019t feel like illustrating, you can use cut-out images instead.\n\nNext, follow the same steps as you did when you exported the faces. Here they are again:\n\nTurn the Template layer off and export the images as PNGs. \nIn the Export dialog, tick the \u201cUse Artboards\u201d checkbox and enter the range with your hats. \nExport at 72ppi to keep things running fast. \nSave your images into the images/ folder in your project.\n\nAdd your accessories to config.js\nIn config.js, add a new key to the customProps object that describes the group of accessories that you just created. Its value should be an array of the filepaths to your images. This is my hats array:\ncustomProps: {\n    hats: [     \n        'images/hat_crown.png',\n        'images/hat_santa.png',\n        'images/hat_tophat.png',\n        'images/hat_antlers.png'\n    ]\n}\nRefresh Chrome and behold, accessories!\n\nCreate as many more accessories as you want\nRepeat the steps above to create as many groups of accessories as you want. I went on to make glasses and hairstyles, so my final illustrator file looks like this:\n\nThe last step is adding your new groups to the config object. List your groups in the order that you want them to be stacked in the DOM. My final output will be hair, then hats, then glasses:\ncustomProps: {\n    hair: [     \n        'images/hair_bowl.png',\n        'images/hair_bob.png'\n    ],  \n    hats: [     \n        'images/hat_crown.png',\n        'images/hat_santa.png',\n        'images/hat_tophat.png',\n        'images/hat_antlers.png'\n    ],\n    glasses: [\n        'images/glasses_aviators.png',\n        'images/glasses_monacle.png'\n    ]\n}\nAnd, there you have it! Randomly generated friends with random accessories. \n\nFeel free to go much crazier than I did. I considered adding a whole group of animals in celebration of the new season of Planet Earth, or even adding Sir David Attenborough himself, or doing a bit of role reversal and featuring the animals with little safari hats! But I digress\u2026\nStep 5: Publish it\nIt\u2019s time to put this in your new tabs! You have two options:\n\nPublish it as a Chrome extension in the Chrome Web Store.\nHost it as a website and point to it with the New Tab Redirect extension.\n\nToday, we\u2019re going to cover Option #1 because I want to show you how to make the simplest Chrome extension possible. However, I recommend Option #2 if you want to keep your project private. Every Chrome extension that you publish is made publicly available, so unless your friends want their faces published to an extension that anyone can use, I\u2019d suggest sticking to Option #2.\nHow to make a simple Chrome extension to replace the new tab page\nAll you need to do to make your project into a Chrome extension is add a manifest.json file to the root of your project with the following contents. There are plenty of other properties that you can add to your manifest file, but these are the only ones that are required for a new tab replacement:\n{\n    \"manifest_version\": 2,\n    \"name\": \"Your extension name\",\n    \"version\": \"1.0\",\n    \"chrome_url_overrides\" : {\n        \"newtab\": \"index.html\"\n    }\n}\nTo test your extension, you\u2019ll need to run it in Developer Mode. Here\u2019s how to do that:\n\nGo to the Extensions page in Chrome by navigating to chrome://extensions/.\nTick the checkbox in the upper-right corner labelled \u201cDeveloper Mode\u201d.\nClick \u201cLoad unpacked extension\u2026\u201d and select this project.\nIf everything is running smoothly, you should see your project when you open a new tab. If there are any errors, they should appear in a yellow box on the Extensions page.\n\nVoila! Like I said, this is a very light example of a Chrome extension, but Google has tons of great documentation on how to take things further. Check it out and see what inspires you.\nShare the love\nNow that you know how to make a new tab extension, go forth and create! But wield your power responsibly. New tabs are opened so often that they\u2019ve become a part of everyday life\u2013just consider how many tabs you opened today. Some people prefer to-do lists in their tabs, and others prefer cats. \nAt the end of the day, let\u2019s make something that makes us happy. Cheers!", "year": "2016", "author": "Leslie Zacharkow", "author_slug": "lesliezacharkow", "published": "2016-12-08T00:00:00+00:00", "url": "https://24ways.org/2016/how-to-make-a-chrome-extension/", "topic": "code"}
{"rowid": 309, "title": "HTTP/2 Server Push and Service Workers: The Perfect Partnership", "contents": "Being a web developer today is exciting! The web has come a long way since its early days and there are so many great technologies that enable us to build faster, better experiences for our users. One of these technologies is HTTP/2 which has a killer feature known as HTTP/2 Server Push.\nDuring this year\u2019s Chrome Developer Summit, I watched a really informative talk by Sam Saccone, a Software Engineer on the Google Chrome team. He gave a talk entitled Planning for Performance, and one of the topics that he covered immediately piqued my interest; the idea that HTTP/2 Server Push and Service Workers were the perfect web performance combination.\n\nIf you\u2019ve never heard of HTTP/2 Server Push before, fear not - it\u2019s not as scary as it sounds. HTTP/2 Server Push simply allows the server to send data to the browser without having to wait for the browser to explicitly request it first. In this article, I am going to run through the basics of HTTP/2 Server Push and show you how, when combined with Service Workers, you can deliver the ultimate in web performance to your users.\nWhat is HTTP/2 Server Push?\nWhen a user navigates to a URL, a browser will make an HTTP request for the underlying web page. The browser will then scan the contents of the HTML document for any assets that it may need to retrieve such as CSS, JavaScript or images. Once it finds any assets that it needs, it will then make multiple HTTP requests for each resource that it needs and begin downloading one by one. While this approach works well, the problem is that each HTTP request means more round trips to the server before any data arrives at the browser. These extra round trips take time and can make your web pages load slower. \nBefore we go any further, let\u2019s see what this might look like when your browser makes a request for a web page. If you were to view this in the developer tools of your browser, it might look a little something like this:\n\nAs you can see from the image above, once the HTML file has been downloaded and parsed, the browser then makes HTTP requests for any assets that it needs. \nThis is where HTTP/2 Server Push comes in. The idea behind HTTP/2 Server Push is that when the browser requests a web page from the server, the server already knows about all the assets that are needed for the web page and \u201cpushes\u201d it to browser. This happens when the first HTTP request for the web page takes place and it eliminates an extra round trip, making your site faster. \nUsing the same example above, let\u2019s \u201cpush\u201d the JavaScript and CSS files instead of waiting for the browser to request them. The image below gives you an idea of what this might look like.\n\nWhoa, that looks different - let\u2019s break it down a little. Firstly, you can see that the JavaScript and CSS files appear earlier in the waterfall chart. You might also notice that the loading times for the files are extremely quick. The browser doesn\u2019t need to make an extra HTTP request to the server, instead it receives the critical files it needs all at once. Much better! \nThere are a number of different approaches when it comes to implementing HTTP/2 Server Push. Adoption is growing and many commercial CDNs such as Akamai and Cloudflare already offer support for Server Push. You can even roll your own implementation depending on your environment. I\u2019ve also previously blogged about building a basic HTTP/2 Server Push example using Node.js. In this post, I\u2019m not going to dive into how to implement HTTP/2 Server Push as that is an entire post in itself! However, I do recommend reading this article to find out more about the inner workings.\nHTTP/2 Server Push is awesome, but it isn\u2019t a magic bullet. It is fantastic for improving the load time of a web page when it first loads for a user, but it isn\u2019t that great when they request the same web page again. The reason for this is that HTTP/2 Server Push is not cache \u201caware\u201d. This means that the server isn\u2019t aware about the state of your client. If you\u2019ve visited a web page before, the server isn\u2019t aware of this and will push the resource again anyway, regardless of whether or not you need it. HTTP/2 Server Push effectively tells the browser that it knows better and that the browser should receive the resources whether it needs them or not. In theory browsers can cancel HTTP/2 Server Push requests if they\u2019re already got something in cache but unfortunately no browsers currently support it. The other issue is that the server will have already started to send some of the resource to the browser by the time the cancellation occurs.\nHTTP/2 Server Push & Service Workers\nSo where do Service Workers fit in? Believe it or not, when combined together HTTP/2 Server Push and Service Workers can be the perfect web performance partnership. If you\u2019ve not heard of Service Workers before, they are worker scripts that run in the background of your website. Simply put, they act as middleman between the client and the browser and enable you to intercept any network requests that come and go from the browser. They are packed with useful features such as caching, push notifications, and background sync. Best of all, they are written in JavaScript, making it easy for web developers to understand.\nUsing Service Workers, you can easily cache assets on a user\u2019s device. This means when a browser makes an HTTP request for an asset, the Service Worker is able to intercept the request and first check if the asset already exists in cache on the users device. If it does, then it can simply return and serve them directly from the device instead of ever hitting the server.\nLet\u2019s stop for a second and analyse what that means. Using HTTP/2 Server Push, you are able to push critical assets to the browser before the browser requests them. Then, using Service Workers you are able to cache these resources so that the browser never needs to make a request to the server again. That means a super fast first load and an even faster second load!\nLet\u2019s put this into action. The following HTML code is a basic web page that retrieves a few images and two JavaScript files.\n<!DOCTYPE html>\n<html>\n<head>\n  <meta charset=\"UTF-8\">\n  <title>HTTP2 Push Demo</title>\n</head>\n<body>\n  <h1>HTTP2 Push</h1>\n  <img src=\"./images/beer-1.png\" width=\"200\" height=\"200\" />\n  <img src=\"./images/beer-2.png\" width=\"200\" height=\"200\" />\n  <br>\n  <br>\n  <img src=\"./images/beer-3.png\" width=\"200\" height=\"200\" />\n  <img src=\"./images/beer-4.png\" width=\"200\" height=\"200\" />\n  <!-- Scripts -->\n  <script async src=\"./js/promise.min.js\"></script>\n  <script async src=\"./js/fetch.js\"></script>\n  <script>\n  // Register the service worker\n  if ('serviceWorker' in navigator) {\n    navigator.serviceWorker.register('./service-worker.js').then(function(registration) {\n      // Registration was successful\n      console.log('ServiceWorker registration successful with scope: ', registration.scope);\n    }).catch(function(err) {\n      // registration failed :(\n      console.log('ServiceWorker registration failed: ', err);\n    });\n  }\n  </script>\n</body>\n</html>\nIn the HTML code above, I am registering a Service Worker file named service-worker.js. In order to start caching assets, I am going to use the Service Worker toolbox . It is a lightweight helper library to help you get started creating your own Service Workers. Using this library, we can actually cache the base web page with the path /push.\nThe Service Worker Toolbox comes with a built-in routing system which is based on the same routing as Express. With just a few lines of code, you can start building powerful caching patterns.\nI\u2019ve add the following code to the service-worker.js file.\n(global => {\n  'use strict';\n\n  // Load the sw-toolbox library.\n  importScripts('/js/sw-toolbox/sw-toolbox.js');\n\n  // The route for any requests\n  toolbox.router.get('/push', global.toolbox.fastest);\n\n  toolbox.router.get('/images/(.*)', global.toolbox.fastest);\n\n  toolbox.router.get('/js/(.*)', global.toolbox.fastest);\n\n  // Ensure that our service worker takes control of the page as soon as possible.\n  global.addEventListener('install', event => event.waitUntil(global.skipWaiting()));\n  global.addEventListener('activate', event => event.waitUntil(global.clients.claim()));\n})(self);\nLet\u2019s break this code down further. Around line 4, I am importing the Service Worker toolbox. Next, I am specifying a route that will listen to any requests that match the URL /push. Because I am also interested in caching the images and JavaScript for that page, I\u2019ve told the toolbox to listen to these routes too.\nThe best thing about the code above is that if any of the assets exist in cache, we will instantly return the cached version instead of waiting for it to download. If the asset doesn\u2019t exist in cache, the code above will add it into cache so that we can retrieve it when it\u2019s needed again.\nYou may also notice the code global.toolbox.fastest - this is important because gives you the compromise of fulfilling from the cache immediately, while firing off an additional HTTP request updating the cache for the next visit.\nBut what does this mean when combined with HTTP/2 Server Push? Well, it means that on the first load of the web page, you are able to \u201cpush\u201d everything to the user at once before the browser has even requested it. The Service Worker activates and starts caching the assets on the users device. The next time a user visits the page, the Service Worker will intercept the request and serve the asset directly from cache. Amazing! \nUsing this technique, the waterfall chart for a repeat visit should look like the image below.\n\nIf you look closely at the image above, you\u2019ll notice that the web page returns almost instantly without ever making an HTTP request over the network. Using the Service Worker library, we cached the base page for the route /push, which allowed us to retrieve this directly from cache.\nWhether used on their own or combined together, the best thing about these two features is that they are the perfect progressive enhancement. If your user\u2019s browser doesn\u2019t support them, they will simply fall back to HTTP/1.1 without Service Workers. Your users may not experience as fast a load time as they would with these two techniques, but it would be no different from their normal experience. HTTP/2 Server Push and Service Workers are really the perfect partners when it comes to web performance.\nSummary\nWhen used correctly, HTTP/2 Server Push and Service Workers can have a positive impact on your site\u2019s load times. Together they mean super fast first load times and even faster repeat views to a web page. Whilst this technique is really effective, it\u2019s worth noting that HTTP/2 push is not a magic bullet. Think about the situations where it might make sense to use it and don\u2019t just simply \u201cpush\u201d everything; it could actually lead to having slower page load times. If you\u2019d like to learn more about the rules of thumb for HTTP/2 Server Push, I recommend reading this article for more information. \nAll of the code in this example is available on my Github repo - if you have any questions, please submit an issue and I\u2019ll get back to you as soon as possible. \nIf you\u2019d like to learn more about this technique and others relating to HTTP/2, I highly recommend watching Sam Saccone\u2019s talk at this years Chrome Developer Summit. \nI\u2019d also like to say a massive thank you to Robin Osborne, Andy Davies and Jeffrey Posnick for helping me review this article before putting it live!", "year": "2016", "author": "Dean Hume", "author_slug": "deanhume", "published": "2016-12-15T00:00:00+00:00", "url": "https://24ways.org/2016/http2-server-push-and-service-workers/", "topic": "code"}
{"rowid": 310, "title": "Fairytale of new Promise", "contents": "There are only four good Christmas songs.\nI know, yeah, JavaScript or whatever. We\u2019ll get to that in a minute, I promise.\nFirst\u2014and I cannot stress this enough\u2014 there are four good Christmas songs. You\u2019re free to disagree with me here, of course, but please try to understand that you will be wrong.\nThey don\u2019t all have the most safe-for-work titles; I can\u2019t list all of them here, but if you choose to let your fingers do the walkin\u2019 to your nearest search engine, I will say that one was released by the band FEAR way back in 1982 and one was on Run the Jewels\u2019 self-titled debut album. The lyrics are a hell of a lot worse than the titles, so maybe wait until you get home from work before you queue them up. Wear headphones, if you\u2019ve got thin walls.\nFor my money, though, the two I can reference by name are the top of that small heap: Tom Waits\u2019 Christmas Card from a Hooker in Minneapolis, and The Pogues\u2019 Fairytale of New York. The former once held the honor of being the only good Christmas song\u2014about which which I was also unequivocally correct, right up until I changed my mind. It\u2019s not the song up for discussion today, but feel free to familiarize yourself just the same\u2014I\u2019ll wait.\nFairytale of New York\u2014the top of the list\u2014starts out by hinting at some pretty standard holiday fare; dreams and cheer and whatnot. Typical seasonal stuff, so long as you ignore that the story seems to be recounted as a drunken flashback in a jail cell. You can probably make a few guesses at the underlying spirit of the song based on that framing: following a lucky break, our bright-eyed protagonists move to New York in search of fame and fortune, only to quickly descend into bad decisions, name-calling, and vaguely festive chaos.\nThis song speaks to me on a couple of levels, not the least of which is as a retelling of my day-to-day interactions with JavaScript. Each day\u2019s melody might vary a little bit, granted, but the lyrics almost always follow a pretty clear arc toward \u201cPARENTAL ADVISORY: EXPLICIT CONTENT.\u201d You might have heard a similar tune yourself; it goes a little somethin\u2019 like setTimeout(function() { console.log( \"this should be happening last\" ); }, 1000); . Callbacks are calling callbacks calling callbacks and something is happening somewhere, as the JavaScript interpreter plods through our code start-to-finish, line-by-line, step-by-step. If we need to take actions based on the results of something that could take its sweet time resolving, well, we\u2019d better fiddle with the order of things to make sure those actions don\u2019t happen too soon.\n\u201cBut I can see a better time,\u201d as the song says, \u201cwhen all our dreams come true.\u201d So, with that Pogues brand of holiday spirit squarely in mind\u2014by which I mean that your humble narrator is almost certainly drunk, and may be incarcerated at the time of publication\u2014gather \u2019round for a story of hope, of hardships, of semi-asynchronous JavaScript programming, and ultimately: of Promise unfulfilled.\nThe Main Thread\nJavaScript is single-minded, in a manner of speaking. Anything we tell the JavaScript runtime to do goes into a single-file queue; you\u2019ll see it referred to as the \u201cmain thread,\u201d or \u201cUI thread.\u201d That thread can be shared by a number of critical browser processes, like rendering and re-rendering parts of the page, and user interactions ranging from the simple\u2014say, highlighting text\u2014to the more complex\u2014interacting with form elements.\nIf that sounds a little scary to you, well, that\u2019s because it is. The more complex our scripts, the more we\u2019re cramming into that single-file main thread, to be processed along with\u2014say\u2014some of our CSS animations. Too much JavaScript clogging up the main thread means a lot of user-facing performance jankiness. Getting away from that single thread is a big part of all the excitement around Web Workers, which allow us to offload entire scripts into their own dedicated background threads\u2014though not without limitations of their own. Outside of Web Workers, that everything-thread is the only game in town: scripts executed one thing at a time, functions calling functions calling functions, taking numbers and crowding up the same deli counter as a user\u2019s interactions\u2014which, in this already strained metaphor, would be ham, I guess?\nAsynchronous JavaScript\nNow, those queued actions may include asynchronous things. For example: AJAX callbacks, setTimeout/setInterval, and addEventListener won\u2019t block the main thread while we\u2019re waiting for a request to come back, a timer to tick away, or an event to trigger. Once those things do kick in, though, the actions they\u2019re meant to perform will get shuffled right back into that single-thread queue.\nThere are a couple of places you might have written asynchronously-fired JavaScript, even if you\u2019re not super familiar with the overarching concept: XMLHttpRequest\u2014\u201cAJAX,\u201d if ya nasty\u2014or just kicking off a function once a user triggers a click or mouseenter event. Event-driven development is writ a little larger, with the overall flow of the script dictated by events, both internal and external. Writing event-driven JavaScript applications is a step in the right direction for sure\u2014it won\u2019t cure what ails the main thread, but it does work with the medium in a reasonable way. Event-driven development allows us to manage our use of the main thread in a way that makes sense. If any of this rings a bell for you, the motivation for Promises should feel familiar.\nFor example, a custom init event might kick things off, and fire a create event that applies our classes and restructures our markup which, on completion, fires a bindEvents event to handle all the event listeners for user interaction. There might not sound like much difference between that and one big function that kicks off, manipulates the DOM, and binds our events line-by-line\u2014but in a script of sufficient size and complexity we\u2019re not only provided with a decoupled flow through the script, but obvious touchpoints for future updates and a predictable structure for ongoing maintenance. \nThis pattern falls apart a little where we were still creating, binding, and listening for events in the same top-to-bottom, one-item-at-a-time way\u2014we had to set a listener on a given object before the event fires, or nothing would happen:\n// Create the event:\nvar event = document.createEvent( \"Event\" );\n\n// Name the event:\nevent.initEvent( \"doTheStuff\", true, true );\n\n// Listen for the custom `doTheStuff` event on `window`:\nwindow.addEventListener( \"doTheStuff\", initializeEverything );\n\n// Fire the custom event\nwindow.dispatchEvent( event );\nThis example is a little contrived, and this stuff is a lot more manageable for sure with the addition of a framework, but that\u2019s the basic gist: create and name the event, add a listener for the event, and\u2014after setting our listener\u2014dispatch the event.\nEvents and callbacks aren\u2019t the only game in town for weaving our way in and out of the main thread, though\u2014at least, not anymore. \nPromises\nA Promise is, at the risk of sounding sentimental, pure potential\u2014an empty container into which a value eventually results. A Promise can exist in several states: \u201cpending,\u201d while the computation they contain is being performed or \u201cresolved\u201d once that computation is complete. Once resolved, a Promise is \u201cfulfilled\u201d if it gave us back something we expect, or \u201crejected\u201d if it didn\u2019t.\nThe Promise constructor accepts a callback with two arguments: resolve and reject. We perform an action\u2014asynchronous or otherwise\u2014within that callback. If everything in there has gone according to plan, we call resolve. If something has gone awry, we call reject\u2014with an error, conventionally. To illustrate, let\u2019s tack something together with a pretty decent chance of doing what we don\u2019t want: a promise meant only to give us the number 1, but has a chance of giving us back a 2. No reasonable person would ever do this, of course, but I wouldn\u2019t necessarily put it past me.\nvar promisedOne = new Promise( function( resolve, reject ) {\n  var coinToss = Math.floor( Math.random() * 2 ) + 1;\n\n  if( coinToss === 1 ) {\n    resolve( coinToss );\n  } else {\n    reject( new Error( \"That ain\u2019t a one.\" ) );\n  }\n});\nThere\u2019s nothing too surprising in there, after you boil it all down. It\u2019s a little return-y, with the exception that we\u2019re flagging results as \u201cas expected\u201d or \u201csomething went wrong.\u201d\nTapping into that Promise uses another new keyword: then\u2014and as someone who attempts to make sense of JavaScript by breaking it down to plain ol\u2019 human-language, I\u2019m a big fan of this syntax. then is tacked onto our Promise identifier, and does just what it says on the tin: once the Promise is resolved, then do one of two things, both supplied as callbacks: the first in the case of a fulfilled promise, and the second in the case of a rejected one. Those two callbacks will have, as arguments, the results we specified with resolve orreject, respectively. It sounds like a lot in prose, but in code it\u2019s a pretty simple pattern:\npromisedOne.then( function( result ) {\n  console.log( result );\n}, function( error ) {\n  console.error( error );\n});\nIf you\u2019ve spent any time working with AJAX\u2014jQuery-wise, in particular\u2014you\u2019ve seen something like this pattern before: a success callback and an error callback. The state of a promise, once fulfilled or rejected, cannot be changed\u2014any reference we make to promisedOne will have a single, fixed result.\nIt may not look like too much the way I\u2019m using it here, but it\u2019s powerful stuff\u2014a pattern for asynchronously resolving anything. I\u2019ve recently used Promises alongside a script that emulates Font Load Events, to apply webfonts asynchronously and avoid a potential performance hit. Font Face Observer allows us to, as the name implies, determine when the files referenced by our @font-face rules have finished loading. \nvar fontObserver = new FontFaceObserver( \"Fancy Font\" );\n\nfontObserver.check().then(function() {\n  document.documentElement.className += \" fonts-loaded\";\n}, function( error ) {\n  console.error( error );\n});\nfontObserver.check() gives us back a Promise, allowing us to chain on a then containing our callbacks for success and failure. We use the fulfilled callback to bolt a class onto the page once the font file has been fully transferred. We don\u2019t bother including an argument in the first function, since we don\u2019t care about the result itself so much as we care that the promise resolved without error\u2014we\u2019re not doing anything with the resolved value, just adding a class to the page. We do include the error argument, since we\u2019ll want to know what happened should something go wrong.\nNow, this isn\u2019t the tidiest syntax around\u2014at least to my eyes\u2014with those two functions just kinda floating in a then. Luckily there\u2019s an similar alternative syntax; one that I find a bit easier to parse at-a-glance:\nfontObserver.check()\n  .then(function() {\n    document.documentElement.className += \" fonts-loaded\";\n  })\n  .catch(function( error ) {\n    console.log( error );\n  });\nThe first callback inside then provides us with our success state, while the catch provides us with a single, explicit \u201csomething went wrong\u201d callback. The two syntaxes aren\u2019t completely identical in all situations, but for a simple case like this, I find it a little neater.\nThe Common Thread\nI guess I still owe you an explanation, huh. Not about the JavaScript-whatever; I think I\u2019ve explained that plenty. No, I mean Fairytale of New York, and why it\u2019s perched up there at the top of the four (4) song heap.\nFairytale is a sad song, ostensibly. If you follow the main thread\u2014start to finish, line-by-line, step by step\u2014 Fairytale is a sad song. And I can see you out there, visions of Die Hard dancing in your heads: \u201cbut is it a Christmas song?\u201d\nWell, for my money, nothing says \u201cholidays\u201d quite like unreliable narration.\nShane MacGowan, the song\u2019s author, has placed the first verse about \u201cChristmas Eve in the drunk tank\u201d as happening right after the \u201clucky one, came in eighteen-to-one\u201d\u2014not at the chronological end of the story. That means the song might not be mostly drunken flashback, but all of it a single, overarching flashback including a Christmas Eve in protective custody. It could be that the man and woman are, together, recounting times long past\u2014good times and bad times\u2014maybe not even in chronological order. Hell, the \u201cNYPD Choir\u201d mentioned in the chorus? There\u2019s no such thing.\nWe\u2019re not big Christmas folks, my family and I. But just the same, every year, the handful of us get together, and every year\u2014like clockwork\u2014there\u2019s a lull in conversation, there\u2019s a sharp exhale, and Ma says \u201cwe all made it.\u201d Not to a house, not to a dinner, but through another year, to another Christmas. At this point, without fail, someone starts telling a story\u2014and one begets another, and so on. Sometimes the stories are happy, sometimes they\u2019re sad, more often than not they\u2019re both. Some are about things we were lucky to walk away from, some are about a time when another one of us didn\u2019t.\nStart-to-finish, line-by-line, step-by-step, the main thread through the year doesn\u2019t change, and maybe there isn\u2019t a whole lot we can do to change it. But by carefully weaving our way in and out of that thread\u2014stories all out of sync and resolving one way or the other, with the results determined by questionably reliable narrators\u2014we can change the way we interact with it and, little by little, we can start making sense of it.", "year": "2016", "author": "Mat Marquis", "author_slug": "matmarquis", "published": "2016-12-19T00:00:00+00:00", "url": "https://24ways.org/2016/fairytale-of-new-promise/", "topic": "code"}
{"rowid": 313, "title": "Centered Tabs with CSS", "contents": "Doug Bowman\u2019s Sliding Doors is pretty much the de facto way to build tabbed navigation with CSS, and rightfully so \u2013 it is, as they say, rockin\u2019 like Dokken. But since it relies heavily on floats for the positioning of its tabs, we\u2019re constrained to either left- or right-hand navigation. But what if we need a bit more flexibility? What if we need to place our navigation in the center?\n\nStyling the li as a floated block does give us a great deal of control over margin, padding, and other presentational styles. However, we should learn to love the inline box \u2013 with it, we can create a flexible, centered alternative to floated navigation lists.\n\nHumble Beginnings\n\nDo an extra shot of \u2018nog, because you know what\u2019s coming next. That\u2019s right, a simple unordered list:\n\n<div id=\"navigation\">\n     <ul>\n          <li><a href=\"#\"><span>Home</span></a></li>\n          <li><a href=\"#\"><span>About</span></a></li>\n          <li><a href=\"#\"><span>Our Work</span></a></li>\n          <li><a href=\"#\"><span>Products</span></a></li>\n          <li class=\"last\"><a href=\"#\"><span>Contact Us</span></a></li>\n     </ul>\n</div>\n\nIf we were wedded to using floats to style our list, we could easily fix the width of our ul, and trick it out with some margin: 0 auto; love to center it accordingly. But this wouldn\u2019t net us much flexibility: if we ever changed the number of navigation items, or if the user increased her browser\u2019s font size, our design could easily break.\n\nInstead of worrying about floats, let\u2019s take the most basic approach possible: let\u2019s turn our list items into inline elements, and simply use text-align to center them within the ul:\n\n#navigation ul, #navigation ul li {\n     list-style: none;\n     margin: 0;\n     padding: 0;\n}\n\n#navigation ul {\n     text-align: center;\n}\n\n#navigation ul li {\n     display: inline;\n     margin-right: .75em;\n}\n\n#navigation ul li.last {\n     margin-right: 0;\n}\n\nOur first step is sexy, no? Well, okay, not really \u2013 but it gives us a good starting point. We\u2019ve tamed our list by removing its default styles, set the list items to display: inline, and centered the lot. Adding a background color to the links shows us exactly how the different elements are positioned.\n\nNow the fun stuff.\n\nInline Elements, Padding, and You\n\nSo how do we give our links some dimensions? Well, as the CSS specification tells us, the height property isn\u2019t an option for inline elements such as our anchors. However, what if we add some padding to them?\n\n#navigation li a {\n     padding: 5px 1em;\n}\n\nI just love leading questions. Things are looking good, but something\u2019s amiss: as you can see, the padded anchors seem to be escaping their containing list.\n\nThankfully, it\u2019s easy to get things back in line. Our anchors have 5 pixels of padding on their top and bottom edges, right? Well, by applying the same vertical padding to the list, our list will finally \u201ccontain\u201d its child elements once again.\n\n\u2019Tis the Season for Tabbing\n\nNow, we\u2019re finally able to follow the \u201cSliding Doors\u201d model, and tack on some graphics:\n\n#navigation ul li a {\n     background: url(\"tab-right.gif\") no-repeat 100% 0;\n     color: #06C;\n     padding: 5px 0;\n     text-decoration: none;\n}\n\n#navigation ul li a span {\n     background: url(\"tab-left.gif\") no-repeat;\n     padding: 5px 1em;\n}\n\n#navigation ul li a:hover span {\n     color: #69C;\n     text-decoration: underline;\n}\n\nFinally, our navigation\u2019s looking appropriately sexy. By placing an equal amount of padding on the top and bottom of the ul, our tabs are properly \u201ccontained\u201d, and we can subsequently style the links within them.\n\n\n\nBut what if we want them to bleed over the bottom-most border? Easy: we can simply decrease the bottom padding on the list by one pixel, like so.\n\nA Special Note for Special Browsers\n\nThe Mac IE5 users in the audience are likely hopping up and down by now: as they\u2019ve discovered, our centered navigation behaves rather annoyingly in their browser. As Philippe Wittenbergh has reported, Mac IE5 is known to create \u201cphantom links\u201d in a block-level element when text-align is set to any value but the default value of left. Thankfully, Philippe has documented a workaround that gets that [censored] venerable browser to behave. Simply place the following code into your CSS, and the links will be restored to their appropriate width:\n\n/**//*/\n#navigation ul li a {\n     display: inline-block;\n     white-space: nowrap;\n     width: 1px;\n}\n/**/\n\nIE for Windows, however, displays an extra kind of crazy. The padding I\u2019ve placed on my anchors is offsetting the spans that contain the left curve of my tabs; thankfully, these shenanigans are easily straightened out:\n\n/**/\n* html #navigation ul li a {\n     padding: 0;\n}\n/**/\n\nAnd with that, we\u2019re finally finished.\n\nAll set.\n\nAnd that\u2019s it. With your centered navigation in hand, you can finally enjoy those holiday toddies and uncomfortable conversations with your skeevy Uncle Eustace.", "year": "2005", "author": "Ethan Marcotte", "author_slug": "ethanmarcotte", "published": "2005-12-08T00:00:00+00:00", "url": "https://24ways.org/2005/centered-tabs-with-css/", "topic": "code"}
{"rowid": 314, "title": "Easy Ajax with Prototype", "contents": "There\u2019s little more impressive on the web today than a appropriate touch of Ajax. Used well, Ajax brings a web interface much closer to the experience of a desktop app, and can turn a bear of an task into a pleasurable activity.\n\nBut it\u2019s really hard, right? It involves all the nasty JavaScript that no one ever does often enough to get really good at, and the browser support is patchy, and urgh it\u2019s just so much damn effort. Well, the good news is that \u2013 ta-da \u2013 it doesn\u2019t have to be a headache. But man does it still look impressive. Here\u2019s how to amaze your friends.\n\nIntroducing prototype.js\n\nPrototype is a JavaScript framework by Sam Stephenson designed to help make developing dynamic web apps a whole lot easier. In basic terms, it\u2019s a JavaScript file which you link into your page that then enables you to do cool stuff.\n\nThere\u2019s loads of capability built in, a portion of which covers our beloved Ajax. The whole thing is freely distributable under an MIT-style license, so it\u2019s good to go. What a nice man that Mr Stephenson is \u2013 friends, let us raise a hearty cup of mulled wine to his good name. Cheers! sluurrrrp.\n\nFirst step is to download the latest Prototype and put it somewhere safe. I suggest underneath the Christmas tree.\n\nCutting to the chase\n\nBefore I go on and set up an example of how to use this, let\u2019s just get to the crux. Here\u2019s how Prototype enables you to make a simple Ajax call and dump the results back to the page:\n\nvar url = 'myscript.php';\nvar pars = 'foo=bar';\nvar target = 'output-div';\t\nvar myAjax = new Ajax.Updater(target, url, {method: 'get', parameters: pars});\n\nThis snippet of JavaScript does a GET to myscript.php, with the parameter foo=bar, and when a result is returned, it places it inside the element with the ID output-div on your page.\n\nKnocking up a basic example\n\nSo to get this show on the road, there are three files we need to set up in our site alongside prototype.js. Obviously we need a basic HTML page with prototype.js linked in. This is the page the user interacts with. Secondly, we need our own JavaScript file for the glue between the interface and the stuff Prototype is doing. Lastly, we need the page (a PHP script in my case) that the Ajax is going to make its call too.\n\nSo, to that basic HTML page for the user to interact with. Here\u2019s one I found whilst out carol singing:\n\n<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\"\n    \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n<html xmlns=\"http://www.w3.org/1999/xhtml\" xml:lang=\"en\" lang=\"en\">\n<head>\n    <meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/>\n    <title>Easy Ajax</title>\n    <script type=\"text/javascript\" src=\"prototype.js\"></script>\n    <script type=\"text/javascript\" src=\"ajax.js\"></script>\n</head> \n<body>\n    <form method=\"get\" action=\"greeting.php\" id=\"greeting-form\">\n        <div>\n            <label for=\"greeting-name\">Enter your name:</label>\n            <input id=\"greeting-name\" type=\"text\" />\n            <input id=\"greeting-submit\" type=\"submit\" value=\"Greet me!\" />\n        </div>\n        <div id=\"greeting\"></div>\n    </form>\n</body>\n</html>\n\nAs you can see, I\u2019ve linked in prototype.js, and also a file called ajax.js, which is where we\u2019ll be putting our glue. (Careful where you leave your glue, kids.)\n\nOur basic example is just going to take a name and then echo it back in the form of a seasonal greeting. There\u2019s a form with an input field for a name, and crucially a DIV (greeting) for the result of our call. You\u2019ll also notice that the form has a submit button \u2013 this is so that it can function as a regular form when no JavaScript is available. It\u2019s important not to get carried away and forget the basics of accessibility.\n\nMeanwhile, back at the server\n\nSo we need a script at the server which is going to take input from the Ajax call and return some output. This is normally where you\u2019d hook into a database and do whatever transaction you need to before returning a result. To keep this as simple as possible, all this example here will do is take the name the user has given and add it to a greeting message. Not exactly Web 2-point-HoHoHo, but there you have it.\n\nHere\u2019s a quick PHP script \u2013 greeting.php \u2013 that Santa brought me early.\n\n<?php\n     $the_name = htmlspecialchars($_GET['greeting-name']);\n     echo \"<p>Season's Greetings, $the_name!</p>\";\n?>\n\nYou\u2019ll perhaps want to do something a little more complex within your own projects. Just sayin\u2019.\n\nGluing it all together\n\nInside our ajax.js file, we need to hook this all together. We\u2019re going to take advantage of some of the handy listener routines and such that Prototype also makes available. The first task is to attach a listener to set the scene once the window has loaded. He\u2019s how we attach an onload event to the window object and get it to call a function named init():\n\nEvent.observe(window, 'load', init, false);\n\nNow we create our init() function to do our evil bidding. Its first job of the day is to hide the submit button for those with JavaScript enabled. After that, it attaches a listener to watch for the user typing in the name field.\n\nfunction init(){\n     $('greeting-submit').style.display = 'none';\n     Event.observe('greeting-name', 'keyup', greet, false);\n}\n\nAs you can see, this is going to make a call to a function called greet() onkeyup in the greeting-name field. That function looks like this:\n\nfunction greet(){\n     var url = 'greeting.php';\n     var pars = 'greeting-name='+escape($F('greeting-name'));\n     var target = 'greeting';\n     var myAjax = new Ajax.Updater(target, url, {method: 'get', parameters: pars});\n}\n\nThe key points to note here are that any user input needs to be escaped before putting into the parameters so that it\u2019s URL-ready. The target is the ID of the element on the page (a DIV in our case) which will be the recipient of the output from the Ajax call.\n\nThat\u2019s it\n\nNo, seriously. That\u2019s everything. Try the example. Amaze your friends with your 1337 Ajax sk1llz.", "year": "2005", "author": "Drew McLellan", "author_slug": "drewmclellan", "published": "2005-12-01T00:00:00+00:00", "url": "https://24ways.org/2005/easy-ajax-with-prototype/", "topic": "code"}
{"rowid": 315, "title": "Edit-in-Place with Ajax", "contents": "Back on day one we looked at using the Prototype library to take all the hard work out of making a simple Ajax call. While that was fun and all, it didn\u2019t go that far towards implementing something really practical. We dipped our toes in, but haven\u2019t learned to swim yet.\n\nSo here is swimming lesson number one. Anyone who\u2019s used Flickr to publish their photos will be familiar with the edit-in-place system used for quickly amending titles and descriptions on photographs. Hovering over an item turns its background yellow to indicate it is editable. A simple click loads the text into an edit box, right there on the page.\n\n\n\nPrototype includes all sorts of useful methods to help reproduce something like this for our own projects. As well as the simple Ajax GETs we learned how to do last time, we can also do POSTs (which we\u2019ll need here) and a whole bunch of manipulations to the user interface \u2013 all through simple library calls. Here\u2019s what we\u2019re building, so let\u2019s do it.\n\nGetting Started\n\nThere are two major components to this process; the user interface manipulation and the Ajax call itself. Our set-up is much the same as last time (you may wish to read the first article if you\u2019ve not already done so). We have a basic HTML page which links in the prototype.js file and our own editinplace.js. Here\u2019s what Santa dropped down my chimney: \n\n<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\"\n     \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n <html xmlns=\"http://www.w3.org/1999/xhtml\" xml:lang=\"en\" lang=\"en\">\n <head>\n     <meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/>\n    <title>Edit-in-Place with Ajax</title>\n     <link href=\"editinplace.css\" rel=\"Stylesheet\" type=\"text/css\" />\n     <script src=\"prototype.js\" type=\"text/javascript\"></script>\n     <script src=\"editinplace.js\" type=\"text/javascript\"></script>    \n</head> \n<body>\n     <h1>Edit-in-place</h1>\n     <p id=\"desc\">Dashing through the snow on a one horse open sleigh.</p>\n </body>\n </html>\n\nSo that\u2019s our page. The editable item is going to be the <p> called desc. The process goes something like this:\n\n\n\tHighlight the area onMouseOver\n\tClear the highlight onMouseOut\n\tIf the user clicks, hide the area and replace with a <textarea> and buttons\n\tRemove all of the above if the user cancels the operation\n\tWhen the Save button is clicked, make an Ajax POST and show that something\u2019s happening\n\tWhen the Ajax call comes back, update the page with the new content\n\n\nEvents and Highlighting\n\nThe first step is to offer feedback to the user that the item is editable. This is done by shading the background colour when the user mouses over. Of course, the CSS :hover pseudo class is a straightforward way to do this, but for three reasons, I\u2019m using JavaScript to switch class names.\n\n\n\t:hover isn\u2019t supported on many elements in Internet Explorer for Windows\n\tI want to keep control over when the highlight switches off after an update, regardless of mouse position\n\tIf JavaScript isn\u2019t available we don\u2019t want to end up with the CSS suggesting it might be\n\n\nWith this in mind, here\u2019s how editinplace.js starts:\n\nEvent.observe(window, 'load', init, false);\n\n function init(){\n     makeEditable('desc');\n }\n\n function makeEditable(id){\n     Event.observe(id, 'click', function(){edit($(id))}, false);\n     Event.observe(id, 'mouseover', function(){showAsEditable($(id))}, false);\n     Event.observe(id, 'mouseout', function(){showAsEditable($(id), true)}, false);\n }\n\n function showAsEditable(obj, clear){\n     if (!clear){\n          Element.addClassName(obj, 'editable');\n     }else{\n          Element.removeClassName(obj, 'editable');\n     }\n }\n\nThe first line attaches an onLoad event to the window, so that the function init() gets called once the page has loaded. In turn, init() sets up all the items on the page that we want to make editable. In this example I\u2019ve just got one, but you can add as many as you like.\n\nThe function madeEditable() attaches the mouseover, mouseout and click events to the item we\u2019re making editable. All showAsEditable does is add and remove the class name editable from the object. This uses the particularly cunning methods Element.addClassName() and Element.removeClassName() which enable you to cleanly add and remove effects without affecting any styling the object may otherwise have.\n\nOh, remember to add a rule for .editable to your style sheet:\n\n.editable{\n     color: #000;\n     background-color: #ffffd3;\n }\n\nThe Switch\n\nAs you can see above, when the user clicks on an editable item, a call is made to the function edit(). This is where we switch out the static item for a nice editable textarea. Here\u2019s how that function looks.\n\nfunction edit(obj){\n     Element.hide(obj);\n\n     var textarea ='<div id=\"' + obj.id + '_editor\">\n          <textarea id=\"' + obj.id + '_edit\" name=\"' + obj.id + '\" rows=\"4\" cols=\"60\">'\n          + obj.innerHTML + '</textarea>';\n\n     var button = '<input id=\"' + obj.id + '_save\" type=\"button\" value=\"SAVE\" /> OR \n          <input id=\"' + obj.id + '_cancel\" type=\"button\" value=\"CANCEL\" /></div>';\n\n     new Insertion.After(obj, textarea+button);\n\n     Event.observe(obj.id+'_save', 'click', function(){saveChanges(obj)}, false);\n     Event.observe(obj.id+'_cancel', 'click', function(){cleanUp(obj)}, false);\n\n }\n\nThe first thing to do is to hide the object. Prototype comes to the rescue with Element.hide() (and of course, Element.show() too). Following that, we build up the textarea and buttons as a string, and then use Insertion.After() to place our new editor underneath the (now hidden) editable object.\n\nThe last thing to do before we leave the user to edit is it attach listeners to the Save and Cancel buttons to call either the saveChanges() function, or to cleanUp() after a cancel.\n\nIn the event of a cancel, we can clean up behind ourselves like so:\n\nfunction cleanUp(obj, keepEditable){\n     Element.remove(obj.id+'_editor');\n     Element.show(obj);\n     if (!keepEditable) showAsEditable(obj, true);\n }\n\nSaving the Changes\n\nThis is where all the Ajax fun occurs. Whilst the previous article introduced Ajax.Updater() for simple Ajax calls, in this case we need a little bit more control over what happens once the response is received. For this purpose, Ajax.Request() is perfect. We can use the onSuccess and onFailure parameters to register functions to handle the response.\n\nfunction saveChanges(obj){\n     var new_content = escape($F(obj.id+'_edit'));\n\n     obj.innerHTML = \"Saving...\";\n     cleanUp(obj, true);\n\n     var success = function(t){editComplete(t, obj);}\n     var failure = function(t){editFailed(t, obj);}\n\n     var url = 'edit.php';\n     var pars = 'id=' + obj.id + '&content=' + new_content;\n     var myAjax = new Ajax.Request(url, {method:'post',\n          postBody:pars, onSuccess:success, onFailure:failure});\n }\n\n function editComplete(t, obj){\n     obj.innerHTML = t.responseText;\n     showAsEditable(obj, true);\n }\n\n function editFailed(t, obj){\n     obj.innerHTML = 'Sorry, the update failed.';\n     cleanUp(obj);\n }\n\nAs you can see, we first grab in the contents of the textarea into the variable new_content. We then remove the editor, set the content of the original object to \u201cSaving\u2026\u201d to show that an update is occurring, and make the Ajax POST.\n\nIf the Ajax fails, editFailed() sets the contents of the object to \u201cSorry, the update failed.\u201d Admittedly, that\u2019s not a very helpful way to handle the error but I have to limit the scope of this article somewhere. It might be a good idea to stow away the original contents of the object (obj.preUpdate = obj.innerHTML) for later retrieval before setting the content to \u201cSaving\u2026\u201d. No one likes a failure \u2013 especially a messy one.\n\nIf the Ajax call is successful, the server-side script returns the edited content, which we then place back inside the object from editComplete, and tidy up.\n\nMeanwhile, back at the server\n\nThe missing piece of the puzzle is the server-side script for committing the changes to your database. Obviously, any solution I provide here is not going to fit your particular application. For the purposes of getting a functional demo going, here\u2019s what I have in PHP.\n\n<?php\n     $id = $_POST['id'];\n     $content = $_POST['content'];\n     echo htmlspecialchars($content);\n ?>\n\nNot exactly rocket science is it? I\u2019m just catching the content item from the POST and echoing it back. For your application to be useful, however, you\u2019ll need to know exactly which record you should be updating. I\u2019m passing in the ID of my <div>, which is not a fat lot of use. You can modify saveChanges() to post back whatever information your app needs to know in order to process the update.\n\nYou should also check the user\u2019s credentials to make sure they have permission to edit whatever it is they\u2019re editing. Basically the same rules apply as with any script in your application.\n\nLimitations\n\nThere are a few bits and bobs that in an ideal world I would tidy up. The first is the error handling, as I\u2019ve already mentioned. The second is that from an idealistic standpoint, I\u2019d rather not be using innerHTML. However, the reality is that it\u2019s presently the most efficient way of making large changes to the document. If you\u2019re serving as XML, remember that you\u2019ll need to replace these with proper DOM nodes.\n\nIt\u2019s also important to note that it\u2019s quite difficult to make something like this universally accessible. Whenever you start updating large chunks of a document based on user interaction, a lot of non-traditional devices don\u2019t cope well. The benefit of this technique, though, is that if JavaScript is unavailable none of the functionality gets implemented at all \u2013 it fails silently. It is for this reason that this shouldn\u2019t be used as a complete replacement for a traditional, universally accessible edit form. It\u2019s a great time-saver for those with the ability to use it, but it\u2019s no replacement.\n\nSee it in action\n\nI\u2019ve put together an example page using the inert PHP script above. That is to say, your edits aren\u2019t committed to a database, so the example is reset when the page is reloaded.", "year": "2005", "author": "Drew McLellan", "author_slug": "drewmclellan", "published": "2005-12-23T00:00:00+00:00", "url": "https://24ways.org/2005/edit-in-place-with-ajax/", "topic": "code"}
{"rowid": 316, "title": "Have Your DOM and Script It Too", "contents": "When working with the XMLHttpRequest object it appears you can only go one of three ways: \n\n\n\tYou can stay true to the colorful moniker du jour and stick strictly to the responseXML property\n\tYou can play with proprietary \u2013 yet widely supported \u2013 fire and inject the value of responseText property into the innerHTML of an element of your choosing\n\tOr you can be eval() and parse JSON or arbitrary JavaScript delivered via responseText\n\n\nBut did you know that there\u2019s a fourth option giving you the best of the latter two worlds? Mint uses this unmentioned approach to grab fresh HTML and run arbitrary JavaScript simultaneously. Without relying on eval(). \u201cBut wait-\u201d, you might say, \u201cwhen would I need to do this?\u201d Besides the example below this technique is handy for things like tab groups that need initialization onload but miss the main onload event handler by a mile thanks to asynchronous scripting.\n\nConsider the problem\n\nOriginally Mint used option 2 to refresh or load new tabs into individual Pepper panes without requiring a full roundtrip to the server. This was all well and good until I introduced the new Client Mode which when enabled allows anyone to view a Mint installation without being logged in. If voyeurs are afoot as Client Mode is disabled, the next time they refresh a pane the entire login page is inserted into the current document. That\u2019s not very helpful so I needed a way to redirect the current document to the login page.\n\n\n\nEnter the solution\n\nWouldn\u2019t it be cool if browsers interpreted the contents of script tags crammed into innerHTML? Sure, but unfortunately, that just wasn\u2019t meant to be. However like the body element, image elements have an onload event handler. When the image has fully loaded the handler runs the code applied to it. See where I\u2019m going with this?\n\nBy tacking a tiny image (think single pixel, transparent spacer gif \u2013 shudder) onto the end of the HTML returned by our Ajax call, we can smuggle our arbitrary JavaScript into the existing document. The image is added to the DOM, and our stowaway can go to town.\n\n<p>This is the results of our Ajax call.</p>\n <img src=\"../images/loaded.gif\" alt=\"\" onload=\"alert('Now that I have your attention...');\" />\n\nPlease be neat\n\nSo we\u2019ve just jammed some meaningless cruft into our DOM. If our script does anything with images this addition could have some unexpected side effects. (Remember The Fly?) So in order to save that poor, unsuspecting element whose innerHTML we just swapped out from sharing Jeff Goldblum\u2019s terrible fate we should tidy up after ourselves. And by using the removeChild method we do just that.\n\n<p>This is the results of our Ajax call.</p>\n <img src=\"../images/loaded.gif\" alt=\"\" \n     onload=\"alert('Now that I have your attention...');this.parentNode.removeChild(this);\" />", "year": "2005", "author": "Shaun Inman", "author_slug": "shauninman", "published": "2005-12-24T00:00:00+00:00", "url": "https://24ways.org/2005/have-your-dom-and-script-it-too/", "topic": "code"}
{"rowid": 318, "title": "Auto-Selecting Navigation", "contents": "In the article Centered Tabs with CSS Ethan laid out a tabbed navigation system which can be centred on the page. A frequent requirement for any tab-based navigation is to be able to visually represent the currently selected tab in some way.\n\nIf you\u2019re using a server-side language such as PHP, it\u2019s quite easy to write something like class=\"selected\" into your markup, but it can be even simpler than that.\n\nLet\u2019s take the navigation div from Ethan\u2019s article as an example.\n\n<div id=\"navigation\">\n     <ul>\n          <li><a href=\"#\"><span>Home</span></a></li>\n          <li><a href=\"#\"><span>About</span></a></li>\n          <li><a href=\"#\"><span>Our Work</span></a></li>\n          <li><a href=\"#\"><span>Products</span></a></li>\n          <li class=\"last\"><a href=\"#\"><span>Contact Us</span></a></li>\n     </ul>\n </div>\n\nAs you can see we have a standard unordered list which is then styled with CSS to look like tabs. By giving each tab a class which describes it\u2019s logical section of the site, if we were to then apply a class to the body tag of each page showing the same, we could write a clever CSS selector to highlight the correct tab on any given page. \n\nSound complicated? Well, it\u2019s not a trivial concept, but actually applying it is dead simple.\n\nModifying the markup\n\nFirst thing is to place a class name on each li in the list:\n\n<div id=\"navigation\">\n     <ul>\n          <li class=\"home\"><a href=\"#\"><span>Home</span></a></li>\n          <li class=\"about\"><a href=\"#\"><span>About</span></a></li>\n          <li class=\"work\"><a href=\"#\"><span>Our Work</span></a></li>\n          <li class=\"products\"><a href=\"#\"><span>Products</span></a></li>\n          <li class=\"last contact\"><a href=\"#\"><span>Contact Us</span></a></li>\n     </ul>\n </div>\n\nThen, on each page of your site, apply the a matching class to the body tag to indicate which section of the site that page is in. For example, on your About page:\n\n<body class=\"about\">...</body>\n\nWriting the CSS selector\n\nYou can now write a single CSS rule to match the selected tab on any given page. The logic is that you want to match the \u2018about\u2019 tab on the \u2018about\u2019 page and the \u2018products\u2019 tab on the \u2018products\u2019 page, so the selector looks like this:\n\nbody.home #navigation li.home,\n body.about #navigation li.about,\n body.work #navigation li.work,\n body.products #navigation li.products,\n body.contact #navigation li.contact{\n      ... whatever styles you need to show the tab selected ...\n } \n\nSo all you need to do when you create a new page in your site is to apply a class to the body tag to say which section it\u2019s in. The CSS will do the rest for you \u2013 without any server-side help.", "year": "2005", "author": "Drew McLellan", "author_slug": "drewmclellan", "published": "2005-12-10T00:00:00+00:00", "url": "https://24ways.org/2005/auto-selecting-navigation/", "topic": "code"}
{"rowid": 319, "title": "Avoiding CSS Hacks for Internet Explorer", "contents": "Back in October, IEBlog issued a call to action, asking developers to clean up their CSS hacks for IE7 testing. Needless to say, a lot of hubbub ensued\u2026 both on IEBlog and elsewhere. My contribution to all of the noise was to suggest that developers review their code and use good CSS hacks. But what makes a good hack?\n\nTantek \u00c7elik, the Godfather of CSS hacks, gave us the answer by explaining how CSS hacks should be designed. In short, they should (1) be valid, (2) target only old/frozen/abandoned user-agents/browsers, and (3) be ugly. Tantek also went on to explain that using a feature of CSS is not a hack.\n\nNow, I\u2019m not a frequent user of CSS hacks, but Tantek\u2019s post made sense to me. In particular, I felt it gave developers direction on how we should be coding to accommodate that sometimes troublesome browser, Internet Explorer. But what I\u2019ve found, through my work with other developers, is that there is still much confusion over the use of CSS hacks and IE. Using examples from the code I\u2019ve seen recently, allow me to demonstrate how to clean up some IE-specific CSS hacks.\n\nThe two hacks that I\u2019ve found most often in the code I\u2019ve seen and worked with are the star html bug and the underscore hack. We know these are both IE-specific by checking Kevin Smith\u2019s CSS Filters chart. Let\u2019s look at each of these hacks and see how we can replace them with the same CSS feature-based solution.\n\nThe star html bug\n\nThis hack violates Tantek\u2019s second rule as it targets current (and future) UAs. I\u2019ve seen this both as a stand alone rule, as well as an override to some other rule in a style sheet. Here are some code samples:\n\n* html div#header {margin-top:-3px;}\n.promo h3 {min-height:21px;}\n* html .promo h3 {height:21px;}\n\nThe underscore hack\n\nThis hack violates Tantek\u2019s first two rules: it\u2019s invalid (according to the W3C CSS Validator) and it targets current UAs. Here\u2019s an example:\n\nol {padding:0; _padding-left:5px;}\n\nUsing child selectors\n\nWe can use the child selector to replace both the star html bug and underscore hack. Here\u2019s how:\n\n Write rules with selectors that would be successfully applied to all browsers. This may mean starting with no declarations in your rule!\n\ndiv#header {}\n.promo h3 {}\nol {padding:0;}\n\n \nTo these rules, add the IE-specific declarations.\n\ndiv#header {margin-top:-3px;}\n.promo h3 {height:21px;}\nol {padding:0 0 0 5px;}\n\n \nAfter each rule, add a second rule. The selector of the second rule must use a child selector. In this new rule, correct any IE-specific declarations previously made.\n\ndiv#header {margin-top:-3px;}\nbody > div#header {margin-top:0;}\n\n.promo h3 {height:21px;}\n.promo > h3 {height:auto; min-height:21px;}\n\nol {padding:0 0 0 5px;}\nhtml > body ol {padding:0;}\n\n \n\nVoil\u00e0 \u2013 no more hacks! There are a few caveats to this that I won\u2019t go into\u2026 but assuming you\u2019re operating in strict mode and barring any really complicated stuff you\u2019re doing in your code, your CSS will still render perfectly across browsers. And while this may make your CSS slightly heftier in size, it should future-proof it for IE7 (or so I hope). Happy holidays!", "year": "2005", "author": "Kimberly Blessing", "author_slug": "kimberlyblessing", "published": "2005-12-17T00:00:00+00:00", "url": "https://24ways.org/2005/avoiding-css-hacks-for-internet-explorer/", "topic": "code"}
{"rowid": 320, "title": "DOM Scripting Your Way to Better Blockquotes", "contents": "Block quotes are great. I don\u2019t mean they\u2019re great for indenting content \u2013 that would be an abuse of the browser\u2019s default styling. I mean they\u2019re great for semantically marking up a chunk of text that is being quoted verbatim. They\u2019re especially useful in blog posts. \n\n<blockquote>\n     <p>Progressive Enhancement, as a label for a strategy for Web design, \n     was coined by Steven Champeon in a series of articles and presentations \n     for Webmonkey and the SxSW Interactive conference.</p>\n </blockquote>\n\nNotice that you can\u2019t just put the quoted text directly between the <blockquote> tags. In order for your markup to be valid, block quotes may only contain block-level elements such as paragraphs.\n\nThere is an optional cite attribute that you can place in the opening <blockquote> tag. This should contain a URL containing the original text you are quoting:\n\n<blockquote cite=\"http://en.wikipedia.org/wiki/Progressive_Enhancement\">\n     <p>Progressive Enhancement, as a label for a strategy for Web design, \n     was coined by Steven Champeon in a series of articles and presentations \n     for Webmonkey and the SxSW Interactive conference.</p>\n </blockquote>\n\nGreat! Except\u2026 the default behavior in most browsers is to completely ignore the cite attribute. Even though it contains important and useful information, the URL in the cite attribute is hidden.\n\nYou could simply duplicate the information with a hyperlink at the end of the quoted text:\n\n<blockquote cite=\"http://en.wikipedia.org/wiki/Progressive_Enhancement\">\n     <p>Progressive Enhancement, as a label for a strategy for Web design, \n     was coined by Steven Champeon in a series of articles and presentations \n     for Webmonkey and the SxSW Interactive conference.</p>\n     <p class=\"attribution\">\n          <a href=\"http://en.wikipedia.org/wiki/Progressive_Enhancement\">source</a>\n     </p>\n </blockquote>\n\nBut somehow it feels wrong to have to write out the same URL twice every time you want to quote something. It could also get very tedious if you have a lot of quotes.\n\nWell, \u201ctedious\u201d is no problem to a programming language, so why not use a sprinkling of DOM Scripting? Here\u2019s a plan for generating an attribution link for every block quote with a cite attribute:\n\n\n\tWrite a function called prepareBlockquotes.\n\tBegin by making sure the browser understands the methods you will be using.\n\tGet all the blockquote elements in the document.\n\tStart looping through each one.\n\tGet the value of the cite attribute.\n\tIf the value is empty, continue on to the next iteration of the loop.\n\tCreate a paragraph.\n\tCreate a link.\n\tGive the paragraph a class of \u201cattribution\u201d.\n\tGive the link an href attribute with the value from the cite attribute.\n\tPlace the text \u201csource\u201d inside the link.\n\tPlace the link inside the paragraph.\n\tPlace the paragraph inside the block quote.\n\tClose the for loop.\n\tClose the function.\n\n\nHere\u2019s how that translates to JavaScript:\n\nfunction prepareBlockquotes() {\n     if (!document.getElementsByTagName || !document.createElement || !document.appendChild) return;\n     var quotes = document.getElementsByTagName(\"blockquote\");\n     for (var i=0; i<quotes.length; i++) {\n          var source = quotes[i].getAttribute(\"cite\");\n          if (!source) continue;\n          var para = document.createElement(\"p\");\n          var link = document.createElement(\"a\");\n          para.className = \"attribution\";\n          link.setAttribute(\"href\",source);\n          link.appendChild(document.createTextNode(\"source\"));\n          para.appendChild(link);\n          quotes[i].appendChild(para);\n     }\n }\n\n\nNow all you need to do is trigger that function when the document has loaded:\n\nwindow.onload = prepareBlockquotes;\n\nBetter yet, use Simon Willison\u2019s handy addLoadEvent function to queue this function up with any others you might want to execute when the page loads.\n\nThat\u2019s it. All you need to do is save this function in a JavaScript file and reference that file from the head of your document using <script> tags.\n\nYou can style the attribution link using CSS. It might look good aligned to the right with a smaller font size.\n\nIf you\u2019re looking for something to do to keep you busy this Christmas, I\u2019m sure that this function could be greatly improved. Here are a few ideas to get you started:\n\n\n\tShould the text inside the generated link be the URL itself?\n\tIf the block quote has a title attribute, how would you take its value and use it as the text inside the generated link?\n\tShould the attribution paragraph be placed outside the block quote? If so, how would you that (remember, there is an insertBefore method but no insertAfter)?\n\tCan you think of other instances of useful information that\u2019s locked away inside attributes? Access keys? Abbreviations?", "year": "2005", "author": "Jeremy Keith", "author_slug": "jeremykeith", "published": "2005-12-05T00:00:00+00:00", "url": "https://24ways.org/2005/dom-scripting-your-way-to-better-blockquotes/", "topic": "code"}
{"rowid": 321, "title": "Tables with Style", "contents": "It might not seem like it but styling tabular data can be a lot of fun. From a semantic point of view, there are plenty of elements to tie some style into. You have cells, rows, row groups and, of course, the table element itself. Adding CSS to a paragraph just isn\u2019t as exciting.\n\nWhere do I start?\n\nFirst, if you have some tabular data (you know, like a spreadsheet with rows and columns) that you\u2019d like to spiffy up, pop it into a table \u2014 it\u2019s rightful place!\n\nTo add more semantics to your table \u2014 and coincidentally to add more hooks for CSS \u2014 break up your table into row groups. There are three types of row groups: the header (thead), the body (tbody) and the footer (tfoot). You can only have one header and one footer but you can have as many table bodies as is appropriate.\n\nSample table example\n\nInspiration\n\nTable Striping\n\nTo improve scanning information within a table, a common technique is to style alternating rows. Also known as zebra tables. Whether you apply it using a class on every other row or turn to JavaScript to accomplish the task, a handy-dandy trick is to use a semi-transparent PNG as your background image. This is especially useful over patterned backgrounds. \n\ntbody tr.odd td {\n     background:transparent url(background.png) repeat top left;\n }\n\n * html tbody tr.odd td {\n     background:#C00;\n     filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(\n          src='background.png', sizingMethod='scale');\n }\n\nWe turn off the default background and apply our PNG hack to have this work in Internet Explorer. \n\nStyling Columns\n\nDid you know you could style a column? That\u2019s right. You can add special column (col) or column group (colgroup) elements. With that you can add border or background styles to the column.\n\n<table>\n     <col id=\"ingredients\">\n     <col id=\"serve12\">\n     <col id=\"serve24\">\n ...\n\nCheck out the example.\n\nFun with Backgrounds\n\nPop in a tiled background to give your table some character! Internet Explorer\u2019s PNG hack unfortunately only works well when applied to a cell.\n\nTo figure out which background will appear over another, just remember the hierarchy:\n\n (bottom) Table \u2192 Column \u2192 Row Group \u2192 Row \u2192 Cell (top)\n\nThe Future is Bright\n\nOnce browser-makers start implementing CSS3, we\u2019ll have more power at our disposal. Just with :first-child and :last-child, you can pull off a scalable version of our previous table with rounded corners and all \u2014 unfortunately, only Firefox manages to pull this one off successfully. And the selector the masses are clamouring for, nth-child, will make zebra tables easy as eggnog.", "year": "2005", "author": "Jonathan Snook", "author_slug": "jonathansnook", "published": "2005-12-19T00:00:00+00:00", "url": "https://24ways.org/2005/tables-with-style/", "topic": "code"}
{"rowid": 322, "title": "Introduction to Scriptaculous Effects", "contents": "Gather around kids, because this year, much like in that James Bond movie with Denise Richards, Christmas is coming early\u2026 in the shape of scrumptuous smooth javascript driven effects at your every whim.\n\nNow what I\u2019m going to do, is take things down a notch. Which is to say, you don\u2019t need to know much beyond how to open a text file and edit it to follow this article. Personally, I for instance can\u2019t code to save my life.\n\nWell, strictly speaking, that\u2019s not entirely true. If my life was on the line, and the code needed was really simple and I wasn\u2019t under any time constraints, then yeah maybe I could hack my way out of it\n\nBut my point is this: I\u2019m not a programmer in the traditional sense of the word. In fact, what I do best, is scrounge code off of other people, take it apart and then put it back together with duct tape, chewing gum and dumb blind luck.\n\nNo, don\u2019t run! That happens to be a good thing in this case. You see, we\u2019re going to be implementing some really snazzy effects (which are considerably more relevant than most people are willing to admit) on your site, and we\u2019re going to do it with the aid of Thomas Fuchs\u2019 amazing Script.aculo.us library. And it will be like stealing candy from a child.\n\nWhat Are We Doing?\n\nI\u2019m going to show you the very basics of implementing the Script.aculo.us javascript library\u2019s Combination Effects. These allow you to fade elements on your site in or out, slide them up and down and so on.\n\nWhy Use Effects at All?\n\nBefore get started though, let me just take a moment to explain how I came to see smooth transitions as something more than smoke and mirror-like effects included for with little more motive than to dazzle and make parents go \u2018uuh, snazzy\u2019.\n\nEarlier this year, I had the good fortune of meeting the kind, gentle and quite knowledgable Matt Webb at a conference here in Copenhagen where we were both speaking (though I will be the first to admit my little talk on Open Source Design was vastly inferior to Matt\u2019s talk). Matt held a talk called Fixing Broken Windows (based on the Broken Windows theory), which really made an impression on me, and which I have since then referred back to several times.\n\nYou can listen to it yourself, as it\u2019s available from Archive.org. Though since Matt\u2019s session uses many visual examples, you\u2019ll have to rely on your imagination for some of the examples he runs through during it. Also, I think it looses audio for a few seconds every once in a while.\n\nAnyway, one of the things Matt talked a lot about, was how our eyes are wired to react to movement. The world doesn\u2019t flickr. It doesn\u2019t disappear or suddenly change and force us to look for the change. Things move smoothly in the real world. They do not pop up.\n\nHow it Works\n\nOnce the necessary files have been included, you trigger an effect by pointing it at the ID of an element. Simple as that.\n\nImplementing the Effects\n\nSo now you know why I believe these effects have a place in your site, and that\u2019s half the battle. Because you see, actually getting these effects up and running, is deceptively simple.\n\nFirst, go and download the latest version of the library (as of this writing, it\u2019s version 1.5 rc5). Unzip itand open it up.\n\nNow we\u2019re going to bypass the instructions in the readme file. Script.aculo.us can do a bunch of quite advanced things, but all we really want from it is its effects. And by sidestepping the rest of the features, we can shave off roughly 80KB of unnecessary javascript, which is well worth it if you ask me.\n\nAs with Drew\u2019s article on Easy Ajax with Prototype, script.aculo.us also uses the Prototype framework by  Sam Stephenson. But contrary to Drew\u2019s article, you don\u2019t have to download Prototype, as a version comes bundled with script.aculo.us (though feel free to upgrade to the latest version if you so please).\n\nSo in the unzipped folder, containing the script.aculo.us files and folder, go into \u2018lib\u2019 and grab the \u2018prototype.js\u2019 file. Move it to whereever you want to store the javascript files. Then fetch the \u2018effects.js\u2019 file from the \u2018src\u2019 folder and put it in the same place.\n\nTo make things even easier for you to get this up and running, I have prepared a small javascript snippet which does some checking to see what you\u2019re trying to do. The script.aculo.us effects are all either \u2018turn this off\u2019 or \u2018turn this on\u2019. What this snippet does, is check to see what state the target currently has (is it on or off?) and then use the necessary effect.\n\nYou can either skip to the end and download the example code, or copy and paste this code into a file manually (I\u2019ll refer to that file as combo.js):\n\nEffect.OpenUp = function(element) {\n     element = $(element);\n     new Effect.BlindDown(element, arguments[1] || {});\n }\n\n Effect.CloseDown = function(element) {\n     element = $(element);\n     new Effect.BlindUp(element, arguments[1] || {});\n }\n\n Effect.Combo = function(element) {\n     element = $(element);\n     if(element.style.display == 'none') { \n          new Effect.OpenUp(element, arguments[1] || {}); \n     }else { \n          new Effect.CloseDown(element, arguments[1] || {}); \n     }\n }\n\nCurrently, this code uses the BlindUp and BlindDown code, which I personally like, but there\u2019s nothing wrong with you changing the effect-type into one of the other effects available.\n\nNow, include the three files in the header of your code, like so:\n\n<script src=\"prototype.js\" type=\"text/javascript\"></script>\n<script src=\"effects.js\" type=\"text/javascript\"></script>\n<script src=\"combo.js\" type=\"text/javascript\"></script>\n\nNow insert the element you want to use the effect on, like so:\n\n<div id=\"content\" style=\"display: none;\">Lorem ipsum dolor sit amet.</div>\n\nThe above element will start out invisible, and when triggered will be revealed. If you want it to start visible, simply remove the style parameter.\n\nAnd now for the trigger \n\n<a href=\"javascript:Effect.Combo('content');\">Click Here</a>\n\nAnd that, is pretty much it. Clicking the link should unfold the DIV targeted by the effect, in this case \u2018content\u2019.\n\nEffect Options\n\nNow, it gets a bit long-haired though. The documentation for script.aculo.us is next to non-existing, and because of that you\u2019ll have to do some digging yourself to appreciate the full potentialof these effects.\n\nFirst of all, what kind of effects are available? Well you can go to the demo page and check them out, or you can open the \u2018effects.js\u2019 file and have a look around, something I recommend doing regardlessly, to gain an overview of what exactly you\u2019re dealing with.\n\nIf you dissect it for long enough, you can even distill some of the options available for the various effects. In the case of the BlindUp and BlindDown effect, which we\u2019re using in our example (as triggered from combo.js), one of the things that would be interesting to play with would be the duration of the effect. If it\u2019s too long, it will feel slow and unresponsive. Too fast and it will be imperceptible.\n\nYou set the options like so:\n\n<a href=\"javascript:Effect.Combo('content', {duration: .2});\">Click Here</a>\n\nThe change from the previous link being the inclusion of , {duration: .2}. In this case, I have lowered the duration to 0.2 second, to really make it feel snappy.\n\nYou can also go all-out and turn on all the bells and whistles of the Blind effect like so (slowed down to a duration of three seconds so you can see what\u2019s going on):\n\n<a href=\"javascript:Effect.Combo('content', {duration: 3, scaleX: true, scaleContent: true});\">Click Here</a>\n\nConclusion\n\nAnd that\u2019s pretty much it. The rest is a matter of getting to know the rest of the effects and their options as well as finding out just when and where to use them. Remember the ancient Chinese saying: Less is more.\n\nDownload Example\n\nI have prepared a very basic example, which you can download and use as a reference point.", "year": "2005", "author": "Michael Heilemann", "author_slug": "michaelheilemann", "published": "2005-12-12T00:00:00+00:00", "url": "https://24ways.org/2005/introduction-to-scriptaculous-effects/", "topic": "code"}
{"rowid": 323, "title": "Introducing UDASSS!", "contents": "Okay. What\u2019s that mean?\n\nUnobtrusive Degradable Ajax Style Sheet Switcher!\n\nBoy are you in for treat today \u2018cause we\u2019re gonna have a whole lotta Ajaxifida Unobtrucitosity CSS swappin\u2019 Fun!\n\nOkay are you really kidding? Nope. I\u2019ve even impressed myself on this one. Unfortunately, I don\u2019t have much time to tell you the ins and outs of what I actually did to get this to work. We\u2019re talking JavaScript, CSS, PHP\u2026Ajax. But don\u2019t worry about that. I\u2019ve always believed that a good A.P.I. is an invisible A.P.I\u2026 and this I felt I achieved. The only thing you need to know is how it works and what to do.\n\nA Quick Introduction Anyway\u2026\n\nFirst of all, the idea is very simple. I wanted something just like what Paul Sowden put together in \nAlternative Style: Working With Alternate Style Sheets from Alistapart Magazine EXCEPT a few minor (not-so-minor actually) differences which I\u2019ve listed briefly below:\n\n\n\n\tAllow users to switch styles without JavaScript enabled (degradable)\n\tPreventing the F.O.U.C. before the window \u2018load\u2019 when getting preferred styles\n\tKeep the JavaScript entirely off our markup (no onclick\u2019s or onload\u2019s)\n\tMake it very very easy to implement (ok, Paul did that too)\n\n\nWhat I did to achieve this was used server-side cookies instead of JavaScript cookies. Hence, PHP. However this isn\u2019t a \u201cPHP style switcher\u201d \u2013 which is where Ajax comes in. For the extreme technical folks, no, there is no xml involved here, or even a callback response. I only say Ajax because everyone knows what \u2018it\u2019 means. With that said, it\u2019s the Ajax that sets the cookies \u2018on the fly\u2019. Got it? Awesome!\n\nWhat you need\n\nLuckily, I\u2019ve done the work for you. It\u2019s all packaged up in a nice zip file (at the end\u2026keep reading for now) \u2013 so from here on out, \njust follow these instructions\n\nAs I\u2019ve mentioned, one of the things we\u2019ll be working with is PHP. So, first things first, open up a file called index and save it with a \u2018.php\u2019 extension.\n\nNext, place the following text at the top of your document (even above your DOCTYPE)\n\n<?php\n require_once('utils/style-switcher.php');\n // style sheet path[, media, title, bool(set as alternate)]\n $styleSheet = new AlternateStyles();\n $styleSheet->add('css/global.css','screen,projection'); // [Global Styles]\n $styleSheet->add('css/preferred.css','screen,projection','Wog Standard'); // [Preferred Styles]\n $styleSheet->add('css/alternate.css','screen,projection','Tiny Fonts',true); // [Alternate Styles]\n $styleSheet->add('css/alternate2.css','screen,projection','Big O Fonts',true); // // [Alternate Styles]\n $styleSheet->getPreferredStyles();\n ?>\n\nThe way this works is REALLY EASY. Pay attention closely.\n\nNotice in the first line we\u2019ve included our style-switcher.php file.\n\nNext we instantiate a PHP class called AlternateStyles() which will allow us to configure our style sheets. \nSo for kicks, let\u2019s just call our object $styleSheet\n\nAs part of the AlternateStyles object, there lies a public method called add. So naturally with our $styleSheet object, we can call it to (da \u2013 da-da-da!) Add Style Sheets!\n\nHow the add() method works\n\nThe add method takes in a possible four arguments, only one is required. However, you\u2019ll want to add some\u2026 since the whole point is working with alternate style sheets.\n\n$path can simply be a uri, absolute, or relative path to your style sheet. $media adds a media attribute to your style sheets. $title gives a name to your style sheets (via title attribute).$alternate (which shows boolean) simply tells us that these are the alternate style sheets.\n\nadd() Tips\n\nFor all global style sheets (meaning the ones that will always be seen and will not be swapped out), simply use the add method as shown next to // [Global Styles].\n\nTo add preferred styles, do the same, but add a \u2018title\u2019.\n\nTo add the alternate styles, do the same as what we\u2019ve done to add preferred styles, but add the extra boolean and set it to true.\n\nNote following when adding style sheets\n\n\n\tMultiple global style sheets are allowed\n\tYou can only have one preferred style sheet (That\u2019s a browser rule)\n\tFeel free to add as many alternate style sheets as you like\n\n\nMoving on\n\nSimply add the following snippet to the <head> of your web document:\n\n<script type=\"text/javascript\" src=\"js/prototype.js\"></script>\n <script type=\"text/javascript\" src=\"js/common.js\"></script>\n <script type=\"text/javascript\" src=\"js/alternateStyles.js\"></script>\n <?php\n $styleSheet->drop();\n ?>\n\nNothing much to explain here. Just use your copy & paste powers.\n\nHow to Switch Styles\n\nWhether you knew it or not, this baby already has the built in \u2018ubobtrusive\u2019 functionality that lets you switch styles by the drop of any link with a class name of \u2018altCss\u2018. Just drop them where ever you like in your document as follows:\n\n<a class=\"altCss\" href=\"index.php?css=Bog_Standard\">Bog Standard</a>\n <a class=\"altCss\" href=\"index.php?css=Really_Small_Fonts\">Small Fonts</a>\n <a class=\"altCss\" href=\"index.php?css=Large_Fonts\">Large Fonts</a>\n\nTake special note where the file is linking to. Yep. Just linking right back to the page we\u2019re on. The only extra parameters we pass in is a variable called \u2018css\u2019 \u2013 and within that we append the names of our style sheets.\n\nAlso take very special note on the names of the style sheets have an under_score to take place of any spaces we might have.\n\nGo ahead\u2026 play around and change the style sheet on the example page. Try disabling JavaScript and refreshing your browser. Still works!\n\nCool eh?\n\nWell, I put this together in one night so it\u2019s still a work in progress and very beta. If you\u2019d like to hear more about it and its future development, be sure stop on by my site where I\u2019ll definitely be maintaining it.\n\nDownload the beta anyway\n\nWell this wouldn\u2019t be fun if there was nothing to download. So we\u2019re hooking you up so you don\u2019t go home (or logoff) unhappy\n\n Download U.D.A.S.S.S | V0.8\n\nMerry Christmas!\n\nThanks for listening and I hope U.D.A.S.S.S. has been well worth your time and will bring many years of Ajaxy Style Switchin\u2019 Fun!\n\nMany Blessings, Merry Christmas and have a great new year!", "year": "2005", "author": "Dustin Diaz", "author_slug": "dustindiaz", "published": "2005-12-18T00:00:00+00:00", "url": "https://24ways.org/2005/introducing-udasss/", "topic": "code"}
{"rowid": 326, "title": "Don't be eval()", "contents": "JavaScript is an interpreted language, and like so many of its peers it includes the all powerful eval() function. eval() takes a string and executes it as if it were regular JavaScript code. It\u2019s incredibly powerful and incredibly easy to abuse in ways that make your code slower and harder to maintain. As a general rule, if you\u2019re using eval() there\u2019s probably something wrong with your design.\n\nCommon mistakes\n\nHere\u2019s the classic misuse of eval(). You have a JavaScript object, foo, and you want to access a property on it \u2013 but you don\u2019t know the name of the property until runtime. Here\u2019s how NOT to do it:\n\nvar property = 'bar';\nvar value = eval('foo.' + property);\n\nYes it will work, but every time that piece of code runs JavaScript will have to kick back in to interpreter mode, slowing down your app. It\u2019s also dirt ugly.\n\nHere\u2019s the right way of doing the above:\n\nvar property = 'bar';\nvar value = foo[property];\n\nIn JavaScript, square brackets act as an alternative to lookups using a dot. The only difference is that square bracket syntax expects a string.\n\nSecurity issues\n\nIn any programming language you should be extremely cautious of executing code from an untrusted source. The same is true for JavaScript \u2013 you should be extremely cautious of running eval() against any code that may have been tampered with \u2013 for example, strings taken from the page query string. Executing untrusted code can leave you vulnerable to cross-site scripting attacks.\n\nWhat\u2019s it good for?\n\nSome programmers say that eval() is B.A.D. \u2013 Broken As Designed \u2013 and should be removed from the language. However, there are some places in which it can dramatically simplify your code. A great example is for use with XMLHttpRequest, a component of the set of tools more popularly known as Ajax. XMLHttpRequest lets you make a call back to the server from JavaScript without refreshing the whole page. A simple way of using this is to have the server return JavaScript code which is then passed to eval(). Here is a simple function for doing exactly that \u2013 it takes the URL to some JavaScript code (or a server-side script that produces JavaScript) and loads and executes that code using XMLHttpRequest and eval().\n\nfunction evalRequest(url) {\n     var xmlhttp = new XMLHttpRequest();\n     xmlhttp.onreadystatechange = function() {\n          if (xmlhttp.readyState==4 && xmlhttp.status==200) {\n               eval(xmlhttp.responseText);\n          }\n     }\n     xmlhttp.open(\"GET\", url, true);\n     xmlhttp.send(null);\n }\n\nIf you want this to work with Internet Explorer you\u2019ll need to include this compatibility patch.", "year": "2005", "author": "Simon Willison", "author_slug": "simonwillison", "published": "2005-12-07T00:00:00+00:00", "url": "https://24ways.org/2005/dont-be-eval/", "topic": "code"}
{"rowid": 327, "title": "Improving Form Accessibility with DOM Scripting", "contents": "The form label element is an incredibly useful little element \u2013 it lets you link the form field unquestionably with the descriptive label text that sits alongside or above it. This is a very useful feature for people using screen readers, but there are some problems with this element.\n\nWhat happens if you have one piece of data that, for various reasons (validation, the way your data is collected/stored etc), needs to be collected using several form elements?\n\nThe classic example is date of birth \u2013 ideally, you\u2019ll ask for the date of birth once but you may have three inputs, one each for day, month and year, that you also need to provide hints about the format required. The problem is that to be truly accessible you need to label each field. So you end up needing something to say \u201cthis is a date of birth\u201d, \u201cthis is the day field\u201d, \u201cthis is the month field\u201d and \u201cthis is the day field\u201d. Seems like overkill, doesn\u2019t it? And it can uglify a form no end.\n\nThere are various ways that you can approach it (and I think I\u2019ve seen them all). Some people omit the label and rely on the title attribute to help the user through; others put text in a label but make the text 1 pixel high and merging in to the background so that screen readers can still get that information. The most common method, though, is simply to set the label to not display at all using the CSS display:none property/value pairing (a technique which, for the time being, seems to work on most screen readers). But perhaps we can do more with this?\n\nThe technique I am suggesting as another alternative is as follows (here comes the pseudo-code):\n\n\n\tStart with a totally valid and accessible form\n\tEnsure that each form input has a label that is linked to its related form control\n\tApply a class to any label that you don\u2019t want to be visible (for example superfluous)\n\n\nThen, through the magic of unobtrusive JavaScript/the DOM, manipulate the page as follows once the page has loaded:\n\n\n\tFind all the label elements that are marked as superfluous and hide them\n\tFind out what input element each of these label elements is related to\n\tThen apply a hint about formatting required for input (gleaned from the original, now-hidden label text) \u2013 add it to the form input as default text\n\tFinally, add in a behaviour that clears or selects the default text (as you choose)\n\n\nSo, here\u2019s the theory put into practice \u2013 a date of birth, grouped using a fieldset, and with the behaviours added in using DOM, and here\u2019s the JavaScript that does the heavy lifting. \n\nBut why not just use display:none? As demonstrated at Juicy Studio, display:none seems to work quite well for hiding label elements. So why use a sledge hammer to crack a nut? In all honesty, this is something of an experiment, but consider the following:\n\n\n\tUsing the DOM, you can add extra levels of help, potentially across a whole form \u2013 or even range of forms \u2013 without necessarily increasing your markup (it goes beyond simply hiding labels)\n\tScreen readers today may  identify a label that is set not to display, but they may not in the future \u2013 this might provide a way around\n\tBy expanding this technique above, it might be possible to visually change the parent container that groups these items \u2013 in this case, a fieldset and legend, which are notoriously difficult to style consistently across different browsers \u2013 while still retaining the underlying semantic/logical structure\n\n\nWell, it\u2019s an idea to think about at least. How is it for you? How else might you use DOM scripting to improve the accessiblity or usability of your forms?", "year": "2005", "author": "Ian Lloyd", "author_slug": "ianlloyd", "published": "2005-12-03T00:00:00+00:00", "url": "https://24ways.org/2005/improving-form-accessibility-with-dom-scripting/", "topic": "code"}
{"rowid": 331, "title": "Splintered Striper", "contents": "Back in March 2004, David F. Miller demonstrated a little bit of DOM scripting magic in his A List Apart article Zebra Tables.\n\nHis script programmatically adds two alternating CSS background colours to table rows, making them more readable and visually pleasing, while saving the document author the tedious task of manually assigning the styling to large static data tables.\n\nAlthough David\u2019s original script performs its duty well, it is nonetheless very specific and limited in its application. It only:\n\n\n\tworks on a single table, identified by its id, with at least a single tbody section\n\tassigns a background colour\n\tallows two colours for odd and even rows\n\tacts on data cells, rather than rows, and then only if they have no class or background colour already defined\n\n\nTaking it further\n\nIn a recent project I found myself needing to apply a striped effect to a medium sized unordered list. Instead of simply modifying the Zebra Tables code for this particular case, I decided to completely recode the script to make it more generic.\n\nBeing more general purpose, the function in my splintered striper experiment is necessarily more complex. Where the original script only expected a single parameter (the id of the target table), the new function is called as follows:\n\nstriper('[parent element tag]','[parent element class or null]','[child element tag]','[comma separated list of classes]')\n\nThis new, fairly self-explanatory function:\n\n\n\ttargets any type of parent element (and, if specified, only those with a certain class)\n\tassigns two or more classes (rather than just two background colours) to the child elements inside the parent\n\tpreserves any existing classes already assigned to the child elements\n\n\nSee it in action\n\nView the demonstration page for three usage examples. For simplicity\u2019s sake, we\u2019re making the calls to the striper function from the body\u2019s onload attribute. In a real deployment situation, we would look at attaching a behaviour to the onload programmatically \u2014 just remember that, as we need to pass variables to the striper function, this would involve creating a wrapper function which would then be attached\u2026something like:\n\nfunction stripe() {\n    striper('tbody','splintered','tr','odd,even');\n}\n\nwindow.onload=stripe;\n\nA final thought\n\nJust because the function is called striper does not mean that it\u2019s limited to purely applying a striped look; as it\u2019s more of a general purpose \u201calternating class assignment\u201d script, you can achieve a whole variety of effects with it.", "year": "2005", "author": "Patrick Lauke", "author_slug": "patricklauke", "published": "2005-12-15T00:00:00+00:00", "url": "https://24ways.org/2005/splintered-striper/", "topic": "code"}
{"rowid": 332, "title": "CSS Layout Starting Points", "contents": "I build a lot of CSS layouts, some incredibly simple, others that cause sleepless nights and remind me of the torturous puzzle books that were given to me at Christmas by aunties concerned for my education. However, most of the time these layouts fit quite comfortably into one of a very few standard formats. For example:\n\n\n\tLiquid, multiple column with no footer\n\tLiquid, multiple column with footer\n\tFixed width, centred\n\n\nRather than starting out with blank CSS and (X)HTML documents every time you need to build a layout, you can fairly quickly create a bunch of layout starting points, that will give you a solid basis for creating the rest of the design and mean that you don\u2019t have to remember how a three column layout with a footer is best achieved every time you come across one! \n\nThese starting points can be really basic, in fact that\u2019s exactly what you want as the final design, the fonts, the colours and so on will be different every time. It\u2019s just the main sections we want to be able to quickly get into place. For example, here is a basic starting point CSS and XHTML document for a fixed width, centred layout with a footer.\n\n <!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\"\n     \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\">\n<html xmlns=\"http://www.w3.org/1999/xhtml\">\n<head>\n     <title>Fixed Width and Centred starting point document</title>\n     <link rel=\"stylesheet\" type=\"text/css\" href=\"fixed-width-centred.css\" />\n     <meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\" />\n</head>\n<body>\n<div id=\"wrapper\">\n     <div id=\"side\">\n          <div class=\"inner\">\n               <p>Sidebar content here</p>\n          </div>\n     </div>\n     <div id=\"content\">\n          <div class=\"inner\">\n               <p>Your main content goes here.</p>\n          </div>\n     </div>\n     <div id=\"footer\">\n          <div class=\"inner\">\n               <p>Ho Ho Ho!</p>\n          </div>\n     </div>\n</div>\n</body>\n</html>\n\n body {\n     text-align: center;\n     min-width: 740px;\n     padding: 0;\n     margin: 0;\n }\n\n #wrapper {\n     text-align: left;\n     width: 740px;\n     margin-left: auto;\n     margin-right: auto;\n     padding: 0;\n }\n\n #content {\n     margin: 0 200px 0 0;\n }\n\n #content .inner {\n     padding-top: 1px;\n     margin: 0 10px 10px 10px;\n }\n\n #side {\n     float: right;\n     width: 180px;\n     margin: 0;\n }\n\n #side .inner {\n     padding-top: 1px;\n     margin: 0 10px 10px 10px;\n }\n\n #footer {\n     margin-top: 10px;\n     clear: both;\n }\n\n #footer .inner {\n     margin: 10px;\n }\n\n9 times out of 10, after figuring out exactly what main elements I have in a layout, I can quickly grab the \u2018one I prepared earlier\u2019, mark-up the relevant sections within the ready-made divs, and from that point on, I only need to worry about the contents of those different areas. The actual layout is tried and tested, one that I know works well in different browsers and that is unlikely to throw me any nasty surprises later on. In addition, considering how the layout is going to work first prevents the problem of developing a layout, then realising you need to put a footer on it, and needing to redevelop the layout as the method you have chosen won\u2019t work well with a footer.\n\nWhile enjoying your mince pies and mulled wine during the \u2018quiet time\u2019 between Christmas and New Year, why not create some starting point layouts of your own? The css-discuss Wiki, CSS layouts section is a great place to find examples that you can try out and find your favourite method of creating the various layout types.", "year": "2005", "author": "Rachel Andrew", "author_slug": "rachelandrew", "published": "2005-12-04T00:00:00+00:00", "url": "https://24ways.org/2005/css-layout-starting-points/", "topic": "code"}
{"rowid": 333, "title": "The Attribute Selector for Fun and (no ad) Profit", "contents": "If I had a favourite CSS selector, it would undoubtedly be the attribute selector (Ed: You really need to get out more). For those of you not familiar with the attribute selector, it allows you to style an element based on the existence, value or partial value of a specific attribute.\n\nAt it\u2019s very basic level you could use this selector to style an element with particular attribute, such as a title attribute.\n\n<abbr title=\"Cascading Style Sheets\">CSS</abbr>\n\nIn this example I\u2019m going to make all <abbr> elements with a title attribute grey. I am also going to give them a dotted bottom border that changes to a solid border on hover. Finally, for that extra bit of feedback, I will change the cursor to a question mark on hover as well. \n\nabbr[title] {\n     color: #666;\n     border-bottom: 1px dotted #666;\n }\n\n abbr[title]:hover {\n     border-bottom-style: solid;\n     cursor: help;\n }\n\nThis provides a nice way to show your site users that <abbr> elements with title tags are special, as they contain extra, hidden information.\n\nMost modern browsers such as Firefox, Safari and Opera support the attribute selector. Unfortunately Internet Explorer 6 and below does not support the attribute selector, but that shouldn\u2019t stop you from adding nice usability embellishments to more modern browsers.\n\nInternet Explorer 7 looks set to implement this CSS2.1 selector, so expect to see it become more common over the next few years.\n\nStyling an element based on the existence of an attribute is all well and good, but it is still pretty limited. Where attribute selectors come into their own is their ability to target the value of an attribute. You can use this for a variety of interesting effects such as styling VoteLinks.\n\nVoteWhats?\n\nIf you haven\u2019t heard of VoteLinks, it is a microformat that allows people to show their approval or disapproval of a links destination by adding a pre-defined keyword to the rev attribute.\n\nFor instance, if you had a particularly bad meal at a restaurant, you could signify your dissaproval by adding a rev attribute with a value of vote-against.\n\n<a href=\"http://www.mommacherri.co.uk/\" rev=\"vote-against\">Momma Cherri's</a>\n\nYou could then highlight these links by adding an image to the right of these links.\n\na[rev=\"vote-against\"]{\n     padding-right: 20px;\n     background: url(images/vote-against.png) no-repeat right top;\n}\n\nThis is a useful technique, but it will only highlight VoteLinks on sites you control. This is where user stylesheets come into effect. If you create a user stylesheet containing this rule, every site you visit that uses VoteLinks will receive your new style.\n\nCool huh?\n\nHowever my absolute favourite use for attribute selectors is as a lightweight form of ad blocking. Most online adverts conform to industry-defined sizes. So if you wanted to block all banner-ad sized images, you could simply add this line of code to your user stylesheet.\n\nimg[width=\"468\"][height=\"60\"],\nimg[width=\"468px\"][height=\"60px\"]  {\n     display: none !important;\n}\n\nTo hide any banner-ad sized element, such as flash movies, applets or iFrames, simply apply the above rule to every element using the universal selector.\n\n*[width=\"468\"][height=\"60\"], *[width=\"468px\"][height=\"60px\"]  {\n     display: none !important;\n}\n\nJust bare in mind when using this technique that you may accidentally hide something that isn\u2019t actually an advert; it just happens to be the same size.\n\nThe Interactive Advertising Bureau lists a number of common ad sizes. Using these dimensions, you can create stylesheet that blocks all the popular ad formats. Apply this as a user stylesheet and you never need to suffer another advert again.\n\nHere\u2019s wishing you a Merry, ad-free Christmas.", "year": "2005", "author": "Andy Budd", "author_slug": "andybudd", "published": "2005-12-11T00:00:00+00:00", "url": "https://24ways.org/2005/the-attribute-selector-for-fun-and-no-ad-profit/", "topic": "code"}
{"rowid": 334, "title": "Transitional vs. Strict Markup", "contents": "When promoting web standards, standardistas often talk about XHTML as being more strict than HTML. In a sense it is, since it requires that all elements are properly closed and that attribute values are quoted. But there are two flavours of XHTML 1.0 (three if you count the Frameset DOCTYPE, which is outside the scope of this article), defined by the Transitional and Strict DOCTYPEs. And HTML 4.01 also comes in those flavours.\n\nThe names reveal what they are about: Transitional DOCTYPEs are meant for those making the transition from older markup to modern ways. Strict DOCTYPEs are actually the default \u2013 the way HTML 4.01 and XHTML 1.0 were constructed to be used.\n\nA Transitional DOCTYPE may be used when you have a lot of legacy markup that cannot easily be converted to comply with a Strict DOCTYPE. But Strict is what you should be aiming for. It encourages, and in some cases enforces, the separation of structure and presentation, moving the presentational aspects from markup to CSS. From the HTML 4 Document Type Definition:\n\n\n\tThis is HTML 4.01 Strict DTD, which excludes the presentation attributes and elements that W3C expects to phase out as support for style sheets matures. Authors should use the Strict DTD when possible, but may use the Transitional DTD when support for presentation attribute and elements is required.\n\n\nAn additional benefit of using a Strict DOCTYPE is that doing so will ensure that browsers use their strictest, most standards compliant rendering modes.\n\nTommy Olsson provides a good summary of the benefits of using Strict over Transitional in Ten questions for Tommy Olsson at Web Standards Group:\n\n\n\tIn my opinion, using a Strict DTD, either HTML 4.01 Strict or XHTML 1.0 Strict, is far more important for the quality of the future web than whether or not there is an X in front of the name. The Strict DTD promotes a separation of structure and presentation, which makes a site so much easier to maintain.\n\n\nFor those looking to start using web standards and valid, semantic markup, it is important to understand the difference between Transitional and Strict DOCTYPEs. For complete listings of the differences between Transitional and Strict DOCTYPEs, see XHTML: Differences between Strict & Transitional, Comparison of Strict and Transitional XHTML, and XHTML1.0 Element Attributes by DTD.\n\nSome of the differences are more likely than others to cause problems for developers moving from a Transitional DOCTYPE to a Strict one, and I\u2019d like to mention a few of those.\n\nElements that are not allowed in Strict DOCTYPEs\n\n\n\tcenter\n\tfont\n\tiframe\n\tstrike\n\tu\n\n\nAttributes not allowed in Strict DOCTYPEs\n\n\n\talign (allowed on elements related to tables: col, colgroup, tbody, td, tfoot, th, thead, and tr)\n\tlanguage\n\tbackground\n\tbgcolor\n\tborder (allowed on table)\n\theight (allowed on img and object)\n\thspace\n\tname (allowed in HTML 4.01 Strict, not allowed on form and img in XHTML 1.0 Strict)\n\tnoshade\n\tnowrap\n\ttarget\n\ttext, link, vlink, and alink\n\tvspace\n\twidth (allowed on img, object, table, col, and colgroup)\n\n\nContent model differences\n\nAn element type\u2019s content model describes what may be contained by an instance of the element type. The most important difference in content models between Transitional and Strict is that blockquote, body, and form elements may only contain block level elements. A few examples:\n\n\n\ttext and images are not allowed immediately inside the body element, and need to be contained in a block level element like p or div\n\tinput elements must not be direct descendants of a form element\n\ttext in blockquote elements must be wrapped in a block level element like p or div\n\n\nGo Strict and move all presentation to CSS\n\nSomething that can be helpful when doing the transition from Transitional to Strict DOCTYPEs is to focus on what each element of the page you are working on is instead of how you want it to look.\n\nWorry about looks later and get the structure and semantics right first.", "year": "2005", "author": "Roger Johansson", "author_slug": "rogerjohansson", "published": "2005-12-13T00:00:00+00:00", "url": "https://24ways.org/2005/transitional-vs-strict-markup/", "topic": "code"}
{"rowid": 335, "title": "Naughty or Nice? CSS Background Images", "contents": "Web Standards based development involves many things \u2013 using semantically sound HTML to provide structure to our documents or web applications, using CSS for presentation and layout, using JavaScript responsibly, and of course, ensuring that all that we do is accessible and interoperable to as many people and user agents as we can.\n\nThis we understand to be good. \n\nAnd it is good. \n\nExcept when we don\u2019t clearly think through the full implications of using those techniques.\n\nWhich often happens when time is short and we need to get things done.\n\nHere are some naughty examples of CSS background images with their nicer, more accessible counterparts.\n\nTransaction related messages\n\nI\u2019m as guilty of this as others (or, perhaps, I\u2019m the only one that has done this, in which case this can serve as my holiday season confessional)  We use lovely little icons to show status messages for a transaction to indicate if the action was successful, or was there a warning or error? For example:\n\n\u201cYour postal/zip code was not in the correct format.\u201d\n\nNotice that we place a nice little icon there, and use background colours and borders to convey a specific message: there was a problem that needs to be fixed. Notice that all of this visual information is now contained in the CSS rules for that div:\n\n<div class=\"error\">\n     <p>Your postal/zip code was not in the correct format.</p>\n </div>\n\n div.error {\n     background: #ffcccc url(../images/error_small.png) no-repeat 5px 4px;\n     color: #900;\n     border-top: 1px solid #c00;\n     border-bottom: 1px solid #c00;\n     padding: 0.25em 0.5em 0.25em 2.5em;\n     font-weight: bold;\n }\n\nUsing this approach also makes it very easy to create a div.success and div.warning CSS rules meaning we have less to change in our HTML.\n\nNice, right?\n\nNo. Naughty. \n\nVisual design communicates\n\nThe CSS is being used to convey very specific information. The choice of icon, the choice of background colour and borders tell us visually that there is something wrong. \n\nWith the icon as a background image \u2013 there is no way to specify any alt text for the icon, and significant meaning is lost. A screen reader user, for example, misses the fact that it is an \u201cerror.\u201d \n\nThe solution? Ask yourself: what is the bare minimum needed to indicate there was an error? Currently in the absence of CSS there will be no icon \u2013 which (I\u2019m hoping you agree) is critical to communicating there was an error.\n\nThe icon should be considered content and not simply presentational.\n\nThe borders and background colour are certainly much less critical \u2013 they belong in the CSS.\n\nLets change the code to place the image directly in the HTML and using appropriate alt text to better communicate the meaning of the icon to all users:\n\n<div class=\"bettererror\">\n     <img src=\"images/error_small.png\" alt=\"Error\" />\n     <p>Your postal/zip code was not in the correct format.</p>\n </div>\n\n div.bettererror {\n     background-color: #ffcccc;\n     color: #900;\n     border-top: 1px solid #c00;\n     border-bottom: 1px solid #c00;\n     padding: 0.25em 0.5em 0.25em 2.5em;\n     font-weight: bold;\n     position: relative;\n     min-height: 1.25em;\n }\n\n div.bettererror img {\n     display: block;\n     position: absolute;\n     left: 0.25em;\n     top: 0.25em;\n     padding: 0;\n     margin: 0;\n }\n\n div.bettererror p {\n     position: absolute;\n     left: 2.5em;\n     padding: 0;\n     margin: 0;\n }\n\nCompare these two examples of transactional messages\n\nStatus of a Record\n\nThis example is pretty straightforward. Consider the following: a real estate listing on a web site. There are three \u201cstates\u201d for a listing: new, normal, and sold. Here\u2019s how they look:\n\nExample of a New Listing\n\nExample of A Sold Listing\n\nIf we (forgive the pun) blindly apply the \u201cuse a CSS background image\u201d technique we clearly run into problems with the new and sold images \u2013 they actually contain content with no way to specify an alternative when placed in the CSS.\n\nIn this case of the \u201cnew\u201d image, we can use the same strategy as we used in the first example (the transaction result). The \u201cnew\u201d image should be considered content and is placed in the HTML as part of the <h2>...</h2> that identifies the listing.\n\nHowever when considering the \u201csold\u201d listing, there are less changes to be made to keep the same look by leaving the \u201cSOLD\u201d image as a background image and providing the equivalent information elsewhere in the listing \u2013 namely, right in the heading.\n\nFor those that can\u2019t see the background image, the status is communicated clearly and right away. A screen reader user that is navigating by heading or viewing a listing will know right away that a particular property is sold.\n\nOf note here is that in both cases (new and sold) placing the status near the beginning of the record helps with a zoom layout as well.\n\nBetter Example of A Sold Listing\n\nSummary\n\nRemember: in the holiday season, its what you give that counts!! Using CSS background images is easy and saves time for you but think of the children. And everyone else for that matter\u2026 \n\nCSS background images should only be used for presentational images, not for those that contain content (unless that content is already represented and readily available elsewhere).", "year": "2005", "author": "Derek Featherstone", "author_slug": "derekfeatherstone", "published": "2005-12-20T00:00:00+00:00", "url": "https://24ways.org/2005/naughty-or-nice-css-background-images/", "topic": "code"}
{"rowid": 336, "title": "Practical Microformats with hCard", "contents": "You\u2019ve probably heard about microformats over the last few months. You may have even read the easily digestible introduction at Digital Web Magazine, but perhaps you\u2019ve not found time to actually implement much yet. That\u2019s understandable, as it can sometimes be difficult to see exactly what you\u2019re adding by applying a microformat to a page. Sure, you\u2019re semantically enhancing the information you\u2019re marking up, and the Semantic Web is a great idea and all, but what benefit is it right now, today? \n\nWell, the answer to that question is simple: you\u2019re adding lots of information that can be and is being used on the web here and now. The big ongoing battle amongst the big web companies if one of territory over information. Everyone\u2019s grasping for as much data as possible. Some of that information many of us are cautious to give away, but a lot of is happy to be freely available. Of the data you\u2019re giving away, it makes sense to give it as much meaning as possible, thus enabling anyone from your friends and family to the giant search company down the road to make the most of it.\n\nOk, enough of the waffle, let\u2019s get working.\n\nIntroducing hCard\n\nYou may have come across hCard. It\u2019s a microformat for describing contact information (or really address book information) from within your HTML. It\u2019s based on the vCard format, which is the format the contacts/address book program on your computer uses. All the usual fields are available \u2013 name, address, town, website, email, you name it.\n\nIf you\u2019re running Firefox and Greasemonkey (or if you can, just to try this out), install this user script. What it does is look for instances of the hCard microformat in a page, and then add in a link to pass any hCards it finds to a web service which will convert it to a vCard. Take a look at the About the author box at the bottom of this article. It\u2019s a hCard, so you should be able to click the icon the user script inserts and add me to your Outlook contacts or OS X Address Book with just a click.\n\nSo microformats are useful after all. Free microformats all round!\n\nImplementing hCard\n\nThis is the really easy bit. All the hCard microformat is, is a bunch of predefined class names that you apply to the markup you\u2019ve probably already got around your contact information. Let\u2019s take the example of the About the author box from this article. Here\u2019s how the markup looks without hCard:\n\n<div class=\"bio\">\n     <h3>About the author</h3>\n     <p>Drew McLellan is a web developer, author and no-good swindler from \n     just outside London, England. At the \n     <a href=\"http://www.webstandards.org/\">Web Standards Project</a> he works \n     on press, strategy and tools. Drew keeps a \n     <a href=\"http://www.allinthehead.com/\">personal weblog</a> covering web \n     development issues and themes.</p>\n</div>\n\nThis is a really simple example because there\u2019s only two key bits of address book information here:- my name and my website address. Let\u2019s push it a little and say that the Web Standards Project is the organisation I work for \u2013 that gives us Name, Company and URL.\n\nTo kick off an hCard, you need a containing object with a class of vcard. The div I already have with a class of bio is perfect for this \u2013 all it needs to do is contain the rest of the contact information.\n\nThe next thing to identify is my name. hCard uses a class of fn (meaning Full Name) to identify a name. As is this case there\u2019s no element surrounding my name, we can just use a span. These changes give us:\n\n<div class=\"bio vcard\">\n     <h3>About the author</h3>\n     <p><span class=\"fn\">Drew McLellan</span> is a web developer...\n\nThe two remaining items are my URL and the organisation I belong to. The class names designated for those are url and org respectively. As both of those items are links in this case, I can apply the classes to those links. So here\u2019s the finished hCard.\n\n<div class=\"bio vcard\">\n     <h3>About the author</h3>\n     <p><span class=\"fn\">Drew McLellan</span> is a web developer, author and \n     no-good swindler from just outside London, England. \n     At the <a class=\"org\" href=\"http://www.webstandards.org/\">Web Standards Project</a> \n     he works on press, strategy and tools. Drew keeps a \n     <a class=\"url\" href=\"http://www.allinthehead.com/\">personal weblog</a> covering web \n     development issues and themes.</p>\n</div>\n\nOK, that was easy. By just applying a few easy class names to the HTML I was already publishing, I\u2019ve implemented an hCard that right now anyone with Greasemonkey can click to add to their address book, that Google and Yahoo! and whoever else can index and work out important things like which websites are associated with my name if they so choose (and boy, will they so choose), and in the future who knows what. In terms of effort, practically nil.\n\nWhere next?\n\nSo that was a trivial example, but to be honest it doesn\u2019t really get much more complex even with the most pernickety permutations. Because hCard is based on vCard (a mature and well thought-out standard), it\u2019s all tried and tested. Here\u2019s some good next steps.\n\n\n\tPlay with the hCard Creator\n\tTake a deep breath and read the spec\n\tStart implementing hCard as you go on your own projects \u2013 it takes very little time\n\n\nhCard is just one of an ever-increasing number of microformats. If this tickled your fancy, I suggest subscribing to the microformats site in your RSS reader to keep in touch with new developments.\n\nWhat\u2019s the take-away?\n\nThe take-away is this. They may sound like just more Web 2-point-HoHoHo hype, but microformats are a well thought-out, and easy to implement way of adding greater depth to the information you publish online. They have some nice benefits right away \u2013 certainly at geek-level \u2013 but in the longer term they become much more significant. We\u2019ve been at this long enough to know that the web has a long, long memory and that what you publish today will likely be around for years. But putting the extra depth of meaning into your documents now you can help guard that they\u2019ll continue to be useful in the future, and not just a bunch of flat ASCII.", "year": "2005", "author": "Drew McLellan", "author_slug": "drewmclellan", "published": "2005-12-06T00:00:00+00:00", "url": "https://24ways.org/2005/practical-microformats-with-hcard/", "topic": "code"}