{"rowid": 156, "title": "Mobile 2.0", "contents": "Thinking 2.0\n\nAs web geeks, we have a thick skin towards jargon. We all know that \u201cWeb 2.0\u201d has been done to death. At Blue Flavor we even have a jargon bucket to penalize those who utter such painfully overused jargon with a cash deposit. But Web 2.0 is a term that has lodged itself into the conscience of the masses. This is actually a good thing.\n\nThe 2.0 suffix was able to succinctly summarize all that was wrong with the Web during the dot-com era as well as the next evolution of an evolving media. While the core technologies actually stayed basically the same, the principles, concepts, interactions and contexts were radically different.\n\nWith that in mind, this Christmas I want to introduce to you the concept of Mobile 2.0. While not exactly a new concept in the mobile community, it is relatively unknown in the web community. And since the foundation of Mobile 2.0 is the web, I figured it was about time for you to get to know each other.\n\nIt\u2019s the Carriers\u2019 world. We just live in it.\n\nBefore getting into Mobile 2.0, I thought first I should introduce you to its older brother. You know the kind, the kid with emotional problems that likes to beat up on you and your friends for absolutely no reason. That is the mobile of today.\n\nThe mobile ecosystem is a very complicated space often and incorrectly compared to the Web. If the Web was a freewheeling hippie \u2014 believing in freedom of information and the unity of man through communities \u2014 then Mobile is the cutthroat capitalist \u2014 out to pillage and plunder for the sake of the almighty dollar. Where the Web is relatively easy to publish to and ultimately make a buck, Mobile is wrought with layers of complexity, politics and obstacles. \n\nI can think of no better way to summarize these challenges than the testimony of Jason Devitt to the United States Congress in what is now being referred to as the \u201ciPhone Hearing.\u201d Jason is the co-founder and CEO of SkyDeck a new wireless startup and former CEO of Vindigo an early pioneer in mobile content.\n\n\n\nAs Jason points out, the mobile ecosystem is a closed door environment controlled by the carriers, forcing the independent publisher to compete or succumb to the will of corporate behemoths.\n\nBut that is all about to change.\n\nIntroducing Mobile 2.0\n\nMobile 2.0 is term used by the mobile community to describe the current revolution happening in mobile. It describes the convergence of mobile and web services, adding portability, ubiquitous connectivity and location-aware services to add physical context to information found on the Web.\n\nIt\u2019s an important term that looks toward the future. Allowing us to imagine the possibilities that mobile technology has long promised but has yet to deliver. It imagines a world where developers can publish mobile content without the current constraints of the mobile ecosystem.\n\nLike the transition from Web 1.0 to 2.0, it signifies the shift away from corporate or brand-centered experiences to user-centered experiences. A focus on richer interactions, driven by user goals. Moving away from proprietary technologies to more open and standard ones, more akin to the Web. And most importantly (from our perspective as web geeks) a shift away from kludgy one-off mobile applications toward using the Web as a platform for content and services.\n\nThis means the world of the Web and the world of Mobile are coming together faster than you can say ARPU (Average Revenue Per User, a staple mobile term to you webbies). And this couldn\u2019t come at a better time. The importance of understanding and addressing user context is quickly becoming a crucial consideration to every interactive experience as the number of ways we access information on the Web increases.\n\nMobile enables the power of the Web, the collective information of millions of people, inherit payment channels and access to just about every other mass media to literally be overlaid on top of the physical world, in context to the person viewing it. \n\nAnyone who can\u2019t imagine how the influence of mobile technology can\u2019t transform how we perform even the simplest of daily tasks needs to get away from their desktop and see the new evolution of information.\n\nThe Instigators\n\nBut what will make Mobile 2.0 move from idillic concept to a hardened market reality in 2008 will be four key technologies. Its my guess that you know each them already.\n\n1. Opera\n\nOpera is like the little train that could. They have been a driving force on moving the Web as we know it on to mobile handsets. Opera technology has proven itself to be highly adaptable, finding itself preloaded on over 40 million handsets, available on televisions sets through Nintendo Wii or via the Nintendo DS.\n\n2. WebKit\n\nMany were surprised when Apple chose to use KHTML instead of Gecko (the guts of Firefox) to power their Safari rendering engine. But WebKit has quickly evolved to be a powerful and flexible browser in the mobile context. WebKit has been in Nokia smartphones for a few years now, is the technology behind Mobile Safari in the iPhone and the iPod Touch and is the default web technology in Google\u2019s open mobile platform effort, Android.\n\n3. The iPhone\n\nThe iPhone has finally brought the concepts and principles of Mobile 2.0 into the forefront of consumers minds and therefore developers\u2019 minds as well. Over 500 web applications have been written specifically for the iPhone since its launch. It\u2019s completely unheard of to see so many applications built for the mobile context in such a short period of time.\n\n4. CSS & Javascript\n\nWeb 2.0 could not exist without the rich interactions offered by CSS and Javascript, and Mobile 2.0 is no different. CSS and Javascript support across multiple phones historically has been, well\u2026 to put it positively\u2026 utter crap.\n\nJavascript finally allows developers to create interesting interactions that support user goals and the mobile context. Specially, AJAX allows us to finally shed the days of bloated Java applications and focus on portable and flexible web applications. While CSS \u2014 namely CSS3 \u2014 allows us to create designs that are as beautiful as they are economical with bandwidth and load times.\n\nWith Leaflets, a collection of iPhone optimized web apps we created, we heavily relied on CSS3 to cache and reuse design elements over and over, minimizing download times while providing an elegant and user-centered design.\n\n\n\nIn Conclusion\n\nIt is the combination of all these instigators that is significantly decreasing the bar to mobile publishing. The market as Jason Devitt describes it, will begin to fade into the background. And maybe the world of mobile will finally start looking more like the Web that we all know and love.\n\nSo after the merriment and celebration of the holiday is over and you look toward the new year to refresh and renew, I hope that you take a seriously consider the mobile medium. \n\nBy this time next year, it is predicted that one-third of humanity will be using mobile devices to access the Web.", "year": "2007", "author": "Brian Fling", "author_slug": "brianfling", "published": "2007-12-21T00:00:00+00:00", "url": "https://24ways.org/2007/mobile-2-0/", "topic": "business"} {"rowid": 158, "title": "10 Ways To Get Design Approval", "contents": "One of the most challenging parts of the web design process is getting design sign off. It can prove time consuming, demoralizing and if you are not careful can lead to a dissatisfied client. What is more you can end up with a design that you are ashamed to include in your portfolio.\n\nHow then can you ensure that the design you produce is the one that gets built? How can you get the client to sign off on your design? Below are 10 tips learnt from years of bitter experience.\n\n1. Define the role of the client and designer\n\nMany of the clients you work with will not have been involved in a web project before. Even if they have they may have worked in a very different way to what you would expect. Take the time at the beginning of the project to explain their role in the design of the site.\n\nThe best approach is to emphasis that their job is to focus on the needs of their users and business. They should concentrate on the broad issues, while you worry about the details of layout, typography and colour scheme.\n\nBy clarifying what you expect from the client, you help them to provide the right kind of input throughout the process.\n\n2. Understand the business\n\nBefore you open up Photoshop or put pen to paper, take the time to make sure you properly understand not only the brief but the organization behind the site. By understanding their business objectives, organizational structure and marketing strategy your design decisions will be better informed.\n\nYou cannot rely upon the brief to provide all of the information you need. It is important to dig deeper and get as good an understanding of their business as possible. This information will prove invaluable when justifying your design decisions.\n\n3. Understand the users\n\nWe all like to think of ourselves as user centric designers, but exactly how much effort do you put into knowing your users before beginning the design process?\n\nTake the time to really understand them the best you can. Try to meet with some real prospective users and get to know their needs. Failing that work with the client to produce user personas to help picture exactly what kind of people they are. \n\nUnderstanding your users not only improves the quality of your work, but also helps move the discussion away from the personal preferences of the client, to the people who\u2019s opinion really matters.\n\n4. Avoid multiple concepts\n\nMany clients like the idea of having the option to choose between multiple design concepts. However, although on the surface this might appear to be a good idea it can ultimately be counterproductive for design sign off.\n\nIn a world of limited budgets it is unwise to waste money on producing designs that are ultimately going to be thrown away. The resources would be better spent refining a single design through multiple iterations.\n\nWhat is more, multiple concepts often cause confusion rather than clarity. It is common for a client to request one element from one design and another from the second. As any designer knows this seldom works.\n\n5. Use mood boards\n\nClients are often better at expressing what they don\u2019t like than what they do. This is one of the reasons why they favour producing multiple design concepts. An alternative less costly approach is to create a series of mood boards. These boards contain a collection of colours, typography and imagery which represent different \u201cmoods\u201d or directions, which the design could take. \n\nMood boards are quick and easy to produce allowing you to try out various design approaches with the client without investing the time needed to produce complete design concepts. This means that by the time you develop a concept the client and designer have already established an understanding about the direction of the design.\n\n6. Say what you like\n\nIt is not uncommon for a client to ask for a design that looks similar to another site they like. The problem is that it can often be hard to establish exactly what it is about the site that attracts them. Also in many cases the sites they like are not something you are keen to emulate!\n\nA better approach that was suggested to me by Andy Budd is to show them sites that you think the design should emulate. Keep a collection of screen captures from well designed sites and pick out a few that are relevant to that particular client. Explain why you feel these designs might suit their project and ask for their feedback. If they don\u2019t like your choices then expose them to more of your collection and see what they pick out.\n\n7. Wireframe the homepage\n\nOften clients find it hard to distinguish between design and content and so sometimes reject a design on the basis that the content is not right. This is particularly true when signing off the homepage.\n\nYou may therefore find it useful to establish the homepage content before producing the design. That way once they see the design they will not be distracted by the content. One of the best ways to do this is by producing a basic wireframe consisting of a series of content boxes. Once this has been approved you will find the sign off of design much easier.\n\n8. Present your designs\n\nAlthough it is true that a good design should speak for itself it still needs presenting to the client. The client needs to understand why you have made the design decisions you have, otherwise they will judge the design purely on personal preference. \n\nTalk them through the design explaining how it meets the needs of their users and business objectives. Refer to the mood boards and preferred sites the client approved and explain how the design is a continuation of those. Never simply email the design through and hope the client interprets your work correctly!\n\n9. Provide written supporting material\n\nUnfortunately, no matter how well you justify the design to the client he is almost certain to want to show it to others. He may need his bosses approval or require internal buy in. At the very least he is going to want to get a second opinion from a friend or colleague.\n\nThe problem with this is that you are not going to be there to present to these people in the same way you did for the client. You cannot expect the client to present your ideas as well as you did. The reality is that you have lost control of how the design is perceived.\n\nOne way to minimize this problem is to provide written documentation supporting the design. This can be a summary of the presentation you gave to the client and allows him to distribute this along with the design. By putting a written explanation with the design you ensure that everybody who sees it gets the same message.\n\n10. Control the feedback\n\nMy final piece of advice for managing design sign off is to control the way you receive feedback. A clients natural inclination will be to give you his personal opinion on the design. This is reinforced because you ask them what they think of the design. Instead ask them what their users will think of the design. Encourage them to think from the users perspective.\n\nAlso encourage them to keep that overarching focus I talked about in my first tip. Their tendency will be to try to improve the design, however that should be your problem not theirs. The role of a client should be to defend the needs of their users and business not do the design. Encourage the client to make comments such as \u201cI am not sure that my female users will like the masculine colours\u201d rather than \u201ccan we make the whole design pink.\u201d It is down to them to identify the problems and for you as the designer to find the most appropriate solution.\n\nSo there you have it. My 10 tips to improve design sign off. Will this ensure design approval every time? Unfortunately not. However it should certainly help smooth the way.", "year": "2007", "author": "Paul Boag", "author_slug": "paulboag", "published": "2007-12-10T00:00:00+00:00", "url": "https://24ways.org/2007/10-ways-to-get-design-approval/", "topic": "business"} {"rowid": 145, "title": "The Neverending (Background Image) Story", "contents": "Everyone likes candy for Christmas, and there\u2019s none better than eye candy. Well, that, and just more of the stuff. Today we\u2019re going to combine both of those good points and look at how to create a beautiful background image that goes on and on\u2026 forever!\n\nOf course, each background image is different, so instead of agonising over each and every pixel, I\u2019m going to concentrate on five key steps that you can apply to any of your own repeating background images. In this example, we\u2019ll look at the Miami Beach background image used on the new FOWA site, which I\u2019m afraid is about as un-festive as you can get.\n\n1. Choose your image wisely\n\nI find there are three main criteria when judging photos you\u2019re considering for repetition manipulation (or \u2018repetulation\u2019, as I like to say)\u2026\n\n\n\tsimplicity (beware of complex patterns)\n\tangle and perspective (watch out for shadows and obvious vanishing points)\n\tconsistent elements (for easy cloning)\n\n\nYou might want to check out this annotated version of the image, where I\u2019ve highlighted elements of the photo that led me to choose it as the right one.\n\nThe original image purchased from iStockPhoto.\n\nThe Photoshopped version used on the FOWA site.\n\n2. The power of horizontal lines\n\nWith the image chosen and your cursor poised for some Photoshop magic, the most useful thing you can do is drag out the edge pixels from one side of the image to create a kind of rough colour \u2018template\u2019 on which to work over. It doesn\u2019t matter which side you choose, although you might find it beneficial to use the one with the simplest spread of colour and complex elements.\n\nClick and hold on the marquee tool in the toolbar and select the \u2018single column marquee tool\u2019, which will span the full height of your document but will only be one pixel wide. Make the selection right at the edge of your document, press ctrl-c / cmd-c to copy the selection you made, create a new layer, and hit ctrl-v / cmd-v to paste the selection onto your new layer. using free transform (ctrl-t / cmd-t), drag out your selection so that it becomes as wide as your entire canvas. \n\nA one-pixel-wide selection stretched out to the entire width of the canvas.\n\n3. Cloning\n\nIt goes without saying that the trusty clone tool is one of the most important in the process of creating a seamlessly repeating background image, but I think it\u2019s important to be fairly loose with it. Always clone on to a new layer so that you\u2019ve got the freedom to move it around, but above all else, use the eraser tool to tweak your cloned areas: let that handle the precision stuff and you won\u2019t have to worry about getting your clones right first time.\n\nIn the example below, you can see how I overcame the problem of the far-left tree shadow being chopped off by cloning the shadow from the tree on its right. \n\nThe edge of the shadow is cut off and needs to be \u2018made\u2019 from a pre-existing element.\n\nThe successful clone completes the missing shadow.\n\nThe two elements are obviously very similar but it doesn\u2019t look like a clone because the majority of the shape is \u2018genuine\u2019 and only a small part is a duplicate. Also, after cloning I transformed the duplicate, erased parts of it, used gradients, and \u2014 ooh, did someone mention gradients?\n\n4. Never underestimate a gradient\n\nFor this image, I used gradients in a similar way to a brush: covering large parts of the canvas with a colour that faded out to a desired point, before erasing certain parts for accuracy.\n\nSeveral of the gradients and brushes that make up the \u2018customised\u2019 part of the image, visible when the main photograph layer is hidden.\n\nThe full composite.\n\nGradients are also a bit of an easy fix: you can use a gradient on one side of the image, flip it horizontally, and then use it again on the opposite side to make a more seamless join.\n\nSpeaking of which\u2026\n\n5. Sewing the seams\n\nNo matter what kind of magic Photoshop dust you sprinkle over your image, there will still always be the area where the two edges meet: that scary \u2018loop\u2019 point. Fret ye not, however, for there\u2019s help at hand in the form of a nice little cheat. Even though the loop point might still be apparent, we can help hide it by doing something to throw viewers off the scent.\n\nThe seam is usually easy to spot because it\u2019s a blank area with not much detail or colour variation, so in order to disguise it, go against the rule: put something across it!\n\nThis isn\u2019t quite as challenging as it may sound, because if we intentionally make our own \u2018object\u2019 to span the join, we can accurately measure the exact halfway point where we need to split it across the two sides of the image. This is exactly what I did with the FOWA background image: I made some clouds!\n\nA sky with no clouds in an unhappy one.\n\nA simple soft white brush creates a cloud-like formation in the sky.\n\nAfter taking the cloud\u2019s opacity down to 20%, I used free transform to highlight the boundaries of the layer. I then moved it over to the right, so that the middle of the layer perfectly aligned with the right side of the canvas.\n\nFinally, I duplicated the layer and did the same in reverse: dragging the layer over to the left and making sure that the middle of the duplicate layer perfectly aligned with the left side of the canvas.\n\nAnd there you have it! Boom! Ta-da! Et Voila! To see the repeating background image in action, visit futureofwebapps.com on a large widescreen monitor or see a simulation of the effect.\n\nThanks for reading, folks. Have a great Christmas!", "year": "2007", "author": "Elliot Jay Stocks", "author_slug": "elliotjaystocks", "published": "2007-12-03T00:00:00+00:00", "url": "https://24ways.org/2007/the-neverending-background-image-story/", "topic": "code"} {"rowid": 147, "title": "Christmas Is In The AIR", "contents": "That\u2019s right, Christmas is coming up fast and there\u2019s plenty of things to do. Get the tree and lights up, get the turkey, buy presents and who know what else. And what about Santa? He\u2019s got a list. I\u2019m pretty sure he\u2019s checking it twice.\n\nSure, we could use an existing list making web site or even a desktop widget. But we\u2019re geeks! What\u2019s the fun in that? Let\u2019s build our own to-do list application and do it with Adobe AIR!\n\nWhat\u2019s Adobe AIR?\n\nAdobe AIR, formerly codenamed Apollo, is a runtime environment that runs on both Windows and OSX (with Linux support to follow). This runtime environment lets you build desktop applications using Adobe technologies like Flash and Flex. Oh, and HTML. That\u2019s right, you web standards lovin\u2019 maniac. You can build desktop applications that can run cross-platform using the trio of technologies, HTML, CSS and JavaScript.\n\nIf you\u2019ve tried developing with AIR before, you\u2019ll need to get re-familiarized with the latest beta release as many things have changed since the last one (such as the API and restrictions within the sandbox.)\n\nTo get started\n\nTo get started in building an AIR application, you\u2019ll need two basic things:\n\n\n\tThe AIR runtime. The runtime is needed to run any AIR-based application.\n\tThe SDK. The software development kit gives you all the pieces to test your application. Unzip the SDK into any folder you wish.\n\n\nYou\u2019ll also want to get your hands on the JavaScript API documentation which you\u2019ll no doubt find yourself getting into before too long. (You can download it, too.)\n\nAlso of interest, some development environments have support for AIR built right in. Aptana doesn\u2019t have support for beta 3 yet but I suspect it\u2019ll be available shortly.\n\nWithin the SDK, there are two main tools that we\u2019ll use: one to test the application (ADL) and another to build a distributable package of our application (ADT). I\u2019ll get into this some more when we get to that stage of development.\n\nBuilding our To-do list application\n\nThe first step to building an application within AIR is to create an XML file that defines our default application settings. I call mine application.xml, mostly because Aptana does that by default when creating a new AIR project. It makes sense though and I\u2019ve stuck with it. Included in the templates folder of the SDK is an example XML file that you can use.\n\nThe first key part to this after specifying things like the application ID, version, and filename, is to specify what the default content should be within the content tags. Enter in the name of the HTML file you wish to load. Within this HTML file will be our application.\n\nui.html\n\nCreate a new HTML document and name it ui.html and place it in the same directory as the application.xml file. The first thing you\u2019ll want to do is copy over the AIRAliases.js file from the frameworks folder of the SDK and add a link to it within your HTML document.\n\n\n\nThe aliases create shorthand links to all of the Flash-based APIs.\n\nNow is probably a good time to explain how to debug your application.\n\nDebugging our application\n\nSo, with our XML file created and HTML file started, let\u2019s try testing our \u2018application\u2019. We\u2019ll need the ADL application located in BIN folder of the SDK and tell it to run the application.xml file.\n\n/path/to/adl /path/to/application.xml\n\nYou can also just drag the XML file onto ADL and it\u2019ll accomplish the same thing. If you just did that and noticed that your blank application didn\u2019t load, you\u2019d be correct. It\u2019s running but isn\u2019t visible. Which at this point means you\u2019ll have to shut down the ADL process. Sorry about that!\n\nChanging the visibility\n\nYou have two ways to make your application visible. You can do it automatically by setting the placing true in the visible tag within the application.xml file.\n\ntrue\n\nThe other way is to do it programmatically from within your application. You\u2019d want to do it this way if you had other startup tasks to perform before showing the interface. To turn the UI on programmatically, simple set the visible property of nativeWindow to true.\n\n\n\nSandbox Security\n\nNow that we have an application that we can see when we start it, it\u2019s time to build the to-do list application. In doing so, you\u2019d probably think that using a JavaScript library is a really good idea \u2014 and it can be but there are some limitations within AIR that have to be considered.\n\nAn HTML document, by default, runs within the application sandbox. You have full access to the AIR APIs but once the onload event of the window has fired, you\u2019ll have a limited ability to make use of eval and other dynamic script injection approaches. This limits the ability of external sources from gaining access to everything the AIR API offers, such as database and local file system access. You\u2019ll still be able to make use of eval for evaluating JSON responses, which is probably the most important if you wish to consume JSON-based services.\n\nIf you wish to create a greater wall of security between AIR and your HTML document loading in external resources, you can create a child sandbox. We won\u2019t need to worry about it for our application so I won\u2019t go any further into it but definitely keep this in mind.\n\nFinally, our application\n\nGetting tired of all this preamble? Let\u2019s actually build our to-do list application. I\u2019ll use jQuery because it\u2019s small and should suit our needs nicely. Let\u2019s begin with some structure:\n\n\n\t\n\t\n\t\n\n\nNow we need to wire up that button to actually add a new item to our to-do list.\n\n\n\nAnd just like that, we\u2019ve got a to-do list! That\u2019s it! Just never close your application and you\u2019ll remember everything. Okay, that\u2019s not very practical. You need to have some way of storing your to-do items until the next time you open up the application.\n\nStoring Data\n\nYou\u2019ve essentially got 4 different ways that you can store data:\n\n\n\tUsing the local database. AIR comes with SQLLite built in. That means you can create tables and insert, update and select data from that database just like on a web server.\n\tUsing the file system. You can also create files on the local machine. You have access to a few folders on the local system such as the documents folder and the desktop.\n\tUsing EcryptedLocalStore. I like using the EcryptedLocalStore because it allows you to easily save key/value pairs and have that information encrypted. All this within just a couple lines of code.\n\tSending the data to a remote API. Our to-do list could sync up with Remember the Milk, for example.\n\n\nTo demonstrate some persistence, we\u2019ll use the file system to store our files. In addition, we\u2019ll let the user specify where the file should be saved. This way, we can create multiple to-do lists, keeping them separate and organized.\n\nThe application is now broken down into 4 basic tasks:\n\n\n\tLoad data from the file system.\n\tPerform any interface bindings.\n\tManage creating and deleting items from the list.\n\tSave any changes to the list back to the file system.\n\n\nLoading in data from the file system\n\nWhen the application starts up, we\u2019ll prompt the user to select a file or specify a new to-do list. Within AIR, there are 3 main file objects: File, FileMode, and FileStream. File handles file and path names, FileMode is used as a parameter for the FileStream to specify whether the file should be read-only or for write access. The FileStream object handles all the read/write activity.\n\nThe File object has a number of shortcuts to default paths like the documents folder, the desktop, or even the application store. In this case, we\u2019ll specify the documents folder as the default location and then use the browseForSave method to prompt the user to specify a new or existing file. If the user specifies an existing file, they\u2019ll be asked whether they want to overwrite it.\n\nvar store = air.File.documentsDirectory;\nvar fileStream = new air.FileStream();\nstore.browseForSave(\"Choose To-do List\");\n\nThen we add an event listener for when the user has selected a file. When the file is selected, we check to see if the file exists and if it does, read in the contents, splitting the file on new lines and creating our list items within the interface.\n\nstore.addEventListener(air.Event.SELECT, fileSelected);\nfunction fileSelected()\n{\n\tair.trace(store.nativePath);\n\t// load in any stored data\n\tvar byteData = new air.ByteArray();\n\tif(store.exists)\n\t{\n\t\tfileStream.open(store, air.FileMode.READ);\n\t\tfileStream.readBytes(byteData, 0, store.size);\n\t\tfileStream.close();\n\n\t\tif(byteData.length > 0)\n\t\t{\n\t\t\tvar s = byteData.readUTFBytes(byteData.length);\n\t\t\toldlist = s.split(\u201c\\r\\n\u201d);\n\n\t\t\t// create todolist items\n\t\t\tfor(var i=0; i < oldlist.length; i++)\n\t\t\t{\n\t\t\t\tcreateItem(oldlist[i], (new Date()).getTime() + i );\n\t\t\t}\n\t\t}\n\t}\n}\n\nPerform Interface Bindings\n\nThis is similar to before where we set the click event on the Add button but we\u2019ve moved the code to save the list into a separate function.\n\n$('#add').click(function(){\n\t\tvar t = $('#text').val();\n\t\tif(t){\n\t\t\t// create an ID using the time\n\t\t\tcreateItem(t, (new Date()).getTime() );\n\t\t}\n})\n\nManage creating and deleting items from the list\n\nThe list management is now in its own function, similar to before but with some extra information to identify list items and with calls to save our list after each change.\n\nfunction createItem(t, id)\n{\n\tif(t.length == 0) return;\n\t// add it to the todo list\n\ttodolist[id] = t;\n\t// use DOM methods to create the new list item\n\tvar li = document.createElement('li');\n\t// the extra space at the end creates a buffer between the text\n\t// and the delete link we're about to add\n\tli.appendChild(document.createTextNode(t + ' '));\n\t// create the delete link\n\tvar del = document.createElement('a');\n\t// this makes it a true link. I feel dirty doing this.\n\tdel.setAttribute('href', '#');\n\tdel.addEventListener('click', function(evt){\n\t\tvar id = this.id.substr(1);\n\t\tdelete todolist[id]; // remove the item from the list\n\t\tthis.parentNode.parentNode.removeChild(this.parentNode);\n\t\tsaveList();\n\t});\n\tdel.appendChild(document.createTextNode('[del]'));\n\tdel.id = 'd' + id;\n\tli.appendChild(del);\n\t// append everything to the list\n\t$('#list').append(li);\n\t//reset the text box\n\t$('#text').val('');\n\tsaveList();\n}\n\nSave changes to the file system\n\nAny time a change is made to the list, we update the file. The file will always reflect the current state of the list and we\u2019ll never have to click a save button. It just iterates through the list, adding a new line to each one.\n\nfunction saveList(){\n\tif(store.isDirectory) return;\n\tvar packet = '';\n\tfor(var i in todolist)\n\t{\n\t\tpacket += todolist[i] + '\\r\\n';\n\t}\n\tvar bytes = new air.ByteArray();\n\tbytes.writeUTFBytes(packet);\n\tfileStream.open(store, air.FileMode.WRITE);\n\tfileStream.writeBytes(bytes, 0, bytes.length);\n\tfileStream.close();\n}\n\nOne important thing to mention here is that we check if the store is a directory first. The reason we do this goes back to our browseForSave call. If the user cancels the dialog without selecting a file first, then the store points to the documentsDirectory that we set it to initially. Since we haven\u2019t specified a file, there\u2019s no place to save the list.\n\nHopefully by this point, you\u2019ve been thinking of some cool ways to pimp out your list. Now we need to package this up so that we can let other people use it, too.\n\nCreating a Package\n\nNow that we\u2019ve created our application, we need to package it up so that we can distribute it. This is a two step process. The first step is to create a code signing certificate (or you can pay for one from Thawte which will help authenticate you as an AIR application developer).\n\nTo create a self-signed certificate, run the following command. This will create a PFX file that you\u2019ll use to sign your application.\n\nadt -certificate -cn todo24ways 1024-RSA todo24ways.pfx mypassword\n\nAfter you\u2019ve done that, you\u2019ll need to create the package with the certificate\n\nadt -package -storetype pkcs12 -keystore todo24ways.pfx todo24ways.air application.xml .\n\nThe important part to mention here is the period at the end of the command. We\u2019re telling it to package up all files in the current directory.\n\nAfter that, just run the AIR file, which will install your application and run it.\n\nImportant things to remember about AIR\n\nWhen developing an HTML application, the rendering engine is Webkit. You\u2019ll thank your lucky stars that you aren\u2019t struggling with cross-browser issues. (My personal favourites are multiple backgrounds and border radius!)\n\nBe mindful of memory leaks. Things like Ajax calls and event binding can cause applications to slowly leak memory over time. Web pages are normally short lived but desktop applications are often open for hours, if not days, and you may find your little desktop application taking up more memory than anything else on your machine!\n\nThe WebKit runtime itself can also be a memory hog, usually taking about 15MB just for itself. If you create multiple HTML windows, it\u2019ll add another 15MB to your memory footprint. Our little to-do list application shouldn\u2019t be much of a concern, though.\n\nThe other important thing to remember is that you\u2019re still essentially running within a Flash environment. While you probably won\u2019t notice this working in small applications, the moment you need to move to multiple windows or need to accomplish stuff beyond what HTML and JavaScript can give you, the need to understand some of the Flash-based elements will become more important.\n\nLastly, the other thing to remember is that HTML links will load within the AIR application. If you want a link to open in the users web browser, you\u2019ll need to capture that event and handle it on your own. The following code takes the HREF from a clicked link and opens it in the default web browser.\n\nair.navigateToURL(new air.URLRequest(this.href));\n\nOnly the beginning\n\nOf course, this is only the beginning of what you can do with Adobe AIR. You don\u2019t have the same level of control as building a native desktop application, such as being able to launch other applications, but you do have more control than what you could have within a web application. Check out the Adobe AIR Developer Center for HTML and Ajax for tutorials and other resources.\n\nNow, go forth and create your desktop applications and hopefully you finish all your shopping before Christmas!\n\nDownload the example files.", "year": "2007", "author": "Jonathan Snook", "author_slug": "jonathansnook", "published": "2007-12-19T00:00:00+00:00", "url": "https://24ways.org/2007/christmas-is-in-the-air/", "topic": "code"} {"rowid": 153, "title": "JavaScript Internationalisation", "contents": "or: Why Rudolph Is More Than Just a Shiny Nose\n\nDunder sat, glumly staring at the computer screen.\n\n\u201cWhat\u2019s up, Dunder?\u201d asked Rudolph, entering the stable and shaking off the snow from his antlers.\n\n\u201cWell,\u201d Dunder replied, \u201cI\u2019ve just finished coding the new reindeer intranet Santa Claus asked me to do. You know how he likes to appear to be at the cutting edge, talking incessantly about Web 2.0, AJAX, rounded corners; he even spooked Comet recently by talking about him as if he were some pushy web server.\n\n\u201cI\u2019ve managed to keep him happy, whilst also keeping it usable, accessible, and gleaming \u2014 and I\u2019m still on the back row of the sleigh! But anyway, given the elves will be the ones using the site, and they come from all over the world, the site is in multiple languages. Which is great, except when it comes to the preview JavaScript I\u2019ve written for the reindeer order form. Here, have a look\u2026\u201d\n\nAs he said that, he brought up the textileRef:8234272265470b85d91702:linkStartMarker:\u201corder\n form in French\u201d:/examples/javascript-internationalisation/initial.fr.html on the screen. (Same in English).\n\n\u201cLooks good,\u201d said Rudolph.\n\n\u201cBut if I add some items,\u201d said Dunder, \u201cthe preview appears in English, as it\u2019s hard-coded in the JavaScript. I don\u2019t want separate code for each language, as that\u2019s just silly \u2014 I thought about just having if statements, but that doesn\u2019t scale at all\u2026\u201d\n\n\u201cAnd there\u2019s more, you aren\u2019t displaying large numbers in French properly, either,\u201d added Rudolph, who had been playing and looking at part of the source code:\n\nfunction update_text() {\n\tvar hay = getValue('hay');\n\tvar carrots = getValue('carrots');\n\tvar bells = getValue('bells');\n\tvar total = 50 * bells + 30 * hay + 10 * carrots;\n\tvar out = 'You are ordering '\n\t\t+ pretty_num(hay) + ' bushel' + pluralise(hay) + ' of hay, '\n\t\t+ pretty_num(carrots) + ' carrot' + pluralise(carrots)\n\t\t+ ', and ' + pretty_num(bells) + ' shiny bell' + pluralise(bells)\n\t\t+ ', at a total cost of ' + pretty_num(total)\n\t\t+ ' gold pieces. Thank you.';\n\tdocument.getElementById('preview').innerHTML = out;\n}\nfunction pretty_num(n) {\n\tn += '';\n\tvar o = '';\n\tfor (i=n.length; i>3; i-=3) {\n\t\to = ',' + n.slice(i-3, i) + o;\n\t}\n\to = n.slice(0, i) + o;\n\treturn o;\n}\nfunction pluralise(n) {\n\tif (n!=1) return 's';\n\treturn '';\n}\n\n\u201cOh, botheration!\u201d cried Dunder. \u201cThis is just so complicated.\u201d\n\n\u201cIt doesn\u2019t have to be,\u201d said Rudolph, \u201cyou just have to think about things in a slightly different way from what you\u2019re used to. As we\u2019re only a simple example, we won\u2019t be able to cover all possibilities, but for starters, we need some way of providing different information to the script dependent on the language. We\u2019ll create a global i18n object, say, and fill it with the correct language information. The first variable we\u2019ll need will be a thousands separator, and then we can change the pretty_num function to use that instead:\n\nfunction pretty_num(n) {\n\tn += '';\n\tvar o = '';\n\tfor (i=n.length; i>3; i-=3) {\n\t\to = i18n.thousands_sep + n.slice(i-3, i) + o;\n\t}\n\to = n.slice(0, i) + o;\n\treturn o;\n}\n\n\u201cThe i18n object will also contain our translations, which we will access through a function called _() \u2014 that\u2019s just an underscore. Other languages have a function of the same name doing the same thing. It\u2019s very simple:\n\nfunction _(s) {\n\tif (typeof(i18n)!='undefined' && i18n[s]) {\n\t\treturn i18n[s];\n\t}\n\treturn s;\n}\n\n\u201cSo if a translation is available and provided, we\u2019ll use that; otherwise we\u2019ll default to the string provided \u2014 which is helpful if the translation begins to lag behind the site\u2019s text at all, as at least something will be output.\u201d\n\n\u201cGot it,\u201d said Dunder. \u201c _('Hello Dunder') will print the translation of that string, if one exists, \u2018Hello Dunder\u2019 if not.\u201d\n\n\u201cExactly. Moving on, your plural function breaks even in English if we have a word where the plural doesn\u2019t add an s \u2014 like \u2018children\u2019.\u201d\n\n\u201cYou\u2019re right,\u201d said Dunder. \u201cHow did I miss that?\u201d\n\n\u201cNo harm done. Better to provide both singular and plural words to the function and let it decide which to use, performing any translation as well:\n\nfunction pluralise(s, p, n) {\n\tif (n != 1) return _(p);\n\treturn _(s);\n}\n\n\u201cWe\u2019d have to provide different functions for different languages as we employed more elves and got more complicated \u2014 for example, in Polish, the word \u2018file\u2019 pluralises like this: 1 plik, 2-4 pliki, 5-21 plik\u00f3w, 22-24 pliki, 25-31 plik\u00f3w, and so on.\u201d (More information on plural forms)\n\n\u201cGosh!\u201d\n\n\u201cNext, as different languages have different word orders, we must stop using concatenation to construct sentences, as it would be impossible for other languages to fit in; we have to keep coherent strings together. Let\u2019s rewrite your update function, and then go through it:\n\nfunction update_text() {\n\tvar hay = getValue('hay');\n\tvar carrots = getValue('carrots');\n\tvar bells = getValue('bells');\n\tvar total = 50 * bells + 30 * hay + 10 * carrots;\n\thay = sprintf(pluralise('%s bushel of hay', '%s bushels of hay', hay), pretty_num(hay));\n\tcarrots = sprintf(pluralise('%s carrot', '%s carrots', carrots), pretty_num(carrots));\n\tbells = sprintf(pluralise('%s shiny bell', '%s shiny bells', bells), pretty_num(bells));\n\tvar list = sprintf(_('%s, %s, and %s'), hay, carrots, bells);\n\tvar out = sprintf(_('You are ordering %s, at a total cost of %s gold pieces.'),\n\t\tlist, pretty_num(total));\n\tout += ' ';\n\tout += _('Thank you.');\n\tdocument.getElementById('preview').innerHTML = out;\n}\n\n\u201c sprintf is a function in many other languages that, given a format string and some variables, slots the variables into place within the string. JavaScript doesn\u2019t have such a function, so we\u2019ll write our own. Again, keep it simple for now, only integers and strings; I\u2019m sure more complete ones can be found on the internet.\n\nfunction sprintf(s) {\n\tvar bits = s.split('%');\n\tvar out = bits[0];\n\tvar re = /^([ds])(.*)$/;\n\tfor (var i=1; i%s gold pieces.\": '',\n\t\"Thank you.\": ''\n};\n\n\u201cIf you implement this across the intranet, you\u2019ll want to investigate the xgettext program, which can automatically extract all strings that need translating from all sorts of code files into a standard .po file (I think Python mode works best for JavaScript). You can then use a different program to take the translated .po file and automatically create the language-specific JavaScript files for us.\u201d (e.g. German .po file for PledgeBank, mySociety\u2019s .po-.js script, example output)\n\nWith a flourish, Rudolph finished editing. \u201cAnd there we go, localised JavaScript in English, French, or German, all using the same main code.\u201d\n\n\u201cThanks so much, Rudolph!\u201d said Dunder.\n\n\u201cI\u2019m not just a pretty nose!\u201d Rudolph quipped. \u201cOh, and one last thing \u2014 please comment liberally explaining the context of strings you use. Your translator will thank you, probably at the same time as they point out the four hundred places you\u2019ve done something in code that only works in your language and no-one else\u2019s\u2026\u201d\n\nThanks to Tim Morley and Edmund Grimley Evans for the French and German translations respectively.", "year": "2007", "author": "Matthew Somerville", "author_slug": "matthewsomerville", "published": "2007-12-08T00:00:00+00:00", "url": "https://24ways.org/2007/javascript-internationalisation/", "topic": "code"} {"rowid": 157, "title": "Capturing Caps Lock", "contents": "One of the more annoying aspects of having to remember passwords (along with having to remember loads of them) is that if you\u2019ve got Caps Lock turned on accidentally when you type one in, it won\u2019t work, and you won\u2019t know why. Most desktop computers alert you in some way if you\u2019re trying to enter your password to log on and you\u2019ve enabled Caps Lock; there\u2019s no reason why the web can\u2019t do the same. What we want is a warning \u2013 maybe the user wants Caps Lock on, because maybe their password is in capitals \u2013 rather than something that interrupts what they\u2019re doing. Something subtle.\n\nBut that doesn\u2019t answer the question of how to do it. Sadly, there\u2019s no way of actually detecting whether Caps Lock is on directly. However, there\u2019s a simple work-around; if the user presses a key, and it\u2019s a capital letter, and they don\u2019t have the Shift key depressed, why then they must have Caps Lock on! Simple. \n\nDOM scripting allows your code to be notified when a key is pressed in an element; when the key is pressed, you get the ASCII code for that key. Capital letters, A to Z, have ASCII codes 65 to 90. So, the code would look something like:\n\non a key press\n\tif the ASCII code for the key is between 65 and 90 *and* if shift is pressed\n\t\twarn the user that they have Caps Lock on, but let them carry on\n\tend if\nend keypress\n\nThe actual JavaScript for this is more complicated, because both event handling and keypress information differ across browsers. Your event handling functions are passed an event object, except in Internet Explorer where you use the global event object; the event object has a which parameter containing the ASCII code for the key pressed, except in Internet Explorer where the event object has a keyCode parameter; some browsers store whether the shift key is pressed in a shiftKey parameter and some in a modifiers parameter. All this boils down to code that looks something like this:\n\nkeypress: function(e) {\n\tvar ev = e ? e : window.event;\n\tif (!ev) {\n\t\treturn;\n\t}\n\tvar targ = ev.target ? ev.target : ev.srcElement;\n\t// get key pressed\n\tvar which = -1;\n\tif (ev.which) {\n\t\twhich = ev.which;\n\t} else if (ev.keyCode) {\n\t\twhich = ev.keyCode;\n\t}\n\t// get shift status\n\tvar shift_status = false;\n\tif (ev.shiftKey) {\n\t\tshift_status = ev.shiftKey;\n\t} else if (ev.modifiers) {\n\t\tshift_status = !!(ev.modifiers & 4);\n\t}\n\n\t// At this point, you have the ASCII code in \u201cwhich\u201d, \n\t// and shift_status is true if the shift key is pressed\n}\n\nThen it\u2019s just a check to see if the ASCII code is between 65 and 90 and the shift key is pressed. (You also need to do the same work if the ASCII code is between 97 (a) and 122 (z) and the shift key is not pressed, because shifted letters are lower-case if Caps Lock is on.)\n\nif (((which >= 65 && which <= 90) && !shift_status) || \n\t((which >= 97 && which <= 122) && shift_status)) {\n\t// uppercase, no shift key\n\t/* SHOW THE WARNING HERE */\n} else {\n\t/* HIDE THE WARNING HERE */\n}\n\nThe warning can be implemented in many different ways: highlight the password field that the user is typing into, show a tooltip, display text next to the field. For simplicity, this code shows the warning as a previously created image, with appropriate alt text. Showing the warning means creating a new tag with DOM scripting, dropping it into the page, and positioning it so that it\u2019s next to the appropriate field. The image looks like this:\n\n\n\nYou know the position of the field the user is typing into (from its offsetTop and offsetLeft properties) and how wide it is (from its offsetWidth properties), so use createElement to make the new img element, and then absolutely position it with style properties so that it appears in the appropriate place (near to the text field). \n\nThe image is a transparent PNG with an alpha channel, so that the drop shadow appears nicely over whatever else is on the page. Because Internet Explorer version 6 and below doesn\u2019t handle transparent PNGs correctly, you need to use the AlphaImageLoader technique to make the image appear correctly.\n\nnewimage = document.createElement('img');\nnewimage.src = \"http://farm3.static.flickr.com/2145/2067574980_3ddd405905_o_d.png\";\nnewimage.style.position = \"absolute\";\nnewimage.style.top = (targ.offsetTop - 73) + \"px\";\nnewimage.style.left = (targ.offsetLeft + targ.offsetWidth - 5) + \"px\";\nnewimage.style.zIndex = \"999\";\nnewimage.setAttribute(\"alt\", \"Warning: Caps Lock is on\");\nif (newimage.runtimeStyle) {\n\t// PNG transparency for IE\n\tnewimage.runtimeStyle.filter += \"progid:DXImageTransform.Microsoft.AlphaImageLoader(src='http://farm3.static.flickr.com/2145/2067574980_3ddd405905_o_d.png',sizingMethod='scale')\";\n}\ndocument.body.appendChild(newimage);\n\nNote that the alt text on the image is also correctly set. Next, all these parts need to be pulled together. On page load, identify all the password fields on the page, and attach a keypress handler to each. (This only needs to be done for password fields because the user can see if Caps Lock is on in ordinary text fields.)\n\nvar inps = document.getElementsByTagName(\"input\");\nfor (var i=0, l=inps.length; i\n\nThe \u201ccreate an image\u201d code from above should only be run if the image is not already showing, so instead of creating a newimage object, create the image and attach it to the password field so that it can be checked for later (and not shown if it\u2019s already showing). For safety, all the code should be wrapped up in its own object, so that its functions don\u2019t collide with anyone else\u2019s functions. So, create a single object called capslock and make all the functions be named methods of the object:\n\nvar capslock = {\n\t... \n\tkeypress: function(e) {\n\t}\n\t...\n}\n\nAlso, the \u201ccreate an image\u201d code is saved into its own named function, show_warning(), and the converse \u201cremove the image\u201d code into hide_warning(). This has the advantage that developers can include the JavaScript library that has been written here, but override what actually happens with their own code, using something like:\n\n\n\n\nAnd that\u2019s all. Simply include the JavaScript library in your pages, override what happens on a warning if that\u2019s more appropriate for what you\u2019re doing, and that\u2019s all you need.\n\n See the script in action.", "year": "2007", "author": "Stuart Langridge", "author_slug": "stuartlangridge", "published": "2007-12-04T00:00:00+00:00", "url": "https://24ways.org/2007/capturing-caps-lock/", "topic": "code"} {"rowid": 161, "title": "Keeping JavaScript Dependencies At Bay", "contents": "As we are writing more and more complex JavaScript applications we run into issues that have hitherto (god I love that word) not been an issue. The first decision we have to make is what to do when planning our app: one big massive JS file or a lot of smaller, specialised files separated by task. \n\nPersonally, I tend to favour the latter, mainly because it allows you to work on components in parallel with other developers without lots of clashes in your version control. It also means that your application will be more lightweight as you only include components on demand.\n\nStarting with a global object\n\nThis is why it is a good plan to start your app with one single object that also becomes the namespace for the whole application, say for example myAwesomeApp:\n\nvar myAwesomeApp = {};\n\nYou can nest any necessary components into this one and also make sure that you check for dependencies like DOM support right up front.\n\nAdding the components\n\nThe other thing to add to this main object is a components object, which defines all the components that are there and their file names.\n\nvar myAwesomeApp = {\n\tcomponents :{\n\t\tformcheck:{\n\t\t\turl:'formcheck.js',\n\t\t\tloaded:false\n\t\t},\n\t\tdynamicnav:{\n\t\t\turl:'dynamicnav.js',\n\t\t\tloaded:false\n\t\t},\n\t\tgallery:{\n\t\t\turl:'gallery.js',\n\t\t\tloaded:false\n\t\t},\n\t\tlightbox:{\n\t\t\turl:'lightbox.js',\n\t\t\tloaded:false\n\t\t}\n\t}\n};\n\nTechnically you can also omit the loaded properties, but it is cleaner this way. The next thing to add is an addComponent function that can load your components on demand by adding new SCRIPT elements to the head of the documents when they are needed.\n\nvar myAwesomeApp = {\n\tcomponents :{\n\t\tformcheck:{\n\t\t\turl:'formcheck.js',\n\t\t\tloaded:false\n\t\t},\n\t\tdynamicnav:{\n\t\t\turl:'dynamicnav.js',\n\t\t\tloaded:false\n\t\t},\n\t\tgallery:{\n\t\t\turl:'gallery.js',\n\t\t\tloaded:false\n\t\t},\n\t\tlightbox:{\n\t\t\turl:'lightbox.js',\n\t\t\tloaded:false\n\t\t}\n\t},\n\taddComponent:function(component){\n\t\tvar c = this.components[component];\n\t\tif(c && c.loaded === false){\n\t\t\tvar s = document.createElement('script');\n\t\t\ts.setAttribute('type', 'text/javascript');\n\t\t\ts.setAttribute('src',c.url);\n\t\t\tdocument.getElementsByTagName('head')[0].appendChild(s);\n\t\t}\n\t}\n};\n\nThis allows you to add new components on the fly when they are not defined:\n\nif(!myAwesomeApp.components.gallery.loaded){\n\tmyAwesomeApp.addComponent('gallery');\n};\n\nVerifying that components have been loaded\n\nHowever, this is not safe as the file might not be available. To make the dynamic adding of components safer each of the components should have a callback at the end of them that notifies the main object that they indeed have been loaded:\n\nvar myAwesomeApp = {\n\tcomponents :{\n\t\tformcheck:{\n\t\t\turl:'formcheck.js',\n\t\t\tloaded:false\n\t\t},\n\t\tdynamicnav:{\n\t\t\turl:'dynamicnav.js',\n\t\t\tloaded:false\n\t\t},\n\t\tgallery:{\n\t\t\turl:'gallery.js',\n\t\t\tloaded:false\n\t\t},\n\t\tlightbox:{\n\t\t\turl:'lightbox.js',\n\t\t\tloaded:false\n\t\t}\n\t},\n\taddComponent:function(component){\n\t\tvar c = this.components[component];\n\t\tif(c && c.loaded === false){\n\t\t\tvar s = document.createElement('script');\n\t\t\ts.setAttribute('type', 'text/javascript');\n\t\t\ts.setAttribute('src',c.url);\n\t\t\tdocument.getElementsByTagName('head')[0].appendChild(s);\n\t\t}\n\t},\n\tcomponentAvailable:function(component){\n\t\tthis.components[component].loaded = true;\n\t}\n}\n\nFor example the gallery.js file should call this notification as a last line:\n\nmyAwesomeApp.gallery = function(){\n\t// [... other code ...]\n}();\nmyAwesomeApp.componentAvailable('gallery');\n\nTelling the implementers when components are available\n\nThe last thing to add (actually as a courtesy measure for debugging and implementers) is to offer a listener function that gets notified when the component has been loaded:\n\nvar myAwesomeApp = {\n\tcomponents :{\n\t\tformcheck:{\n\t\t\turl:'formcheck.js',\n\t\t\tloaded:false\n\t\t},\n\t\tdynamicnav:{\n\t\t\turl:'dynamicnav.js',\n\t\t\tloaded:false\n\t\t},\n\t\tgallery:{\n\t\t\turl:'gallery.js',\n\t\t\tloaded:false\n\t\t},\n\t\tlightbox:{\n\t\t\turl:'lightbox.js',\n\t\t\tloaded:false\n\t\t}\n\t},\n\taddComponent:function(component){\n\t\tvar c = this.components[component];\n\t\tif(c && c.loaded === false){\n\t\t\tvar s = document.createElement('script');\n\t\t\ts.setAttribute('type', 'text/javascript');\n\t\t\ts.setAttribute('src',c.url);\n\t\t\tdocument.getElementsByTagName('head')[0].appendChild(s);\n\t\t}\n\t},\n\tcomponentAvailable:function(component){\n\t\tthis.components[component].loaded = true;\n\t\tif(this.listener){\n\t\t\tthis.listener(component);\n\t\t};\n\t}\n};\n\nThis allows you to write a main listener function that acts when certain components have been loaded, for example:\n\nmyAwesomeApp.listener = function(component){\n\tif(component === 'gallery'){\n\t showGallery();\n\t}\n};\n\nExtending with other components\n\nAs the main object is public, other developers can extend the components object with own components and use the listener function to load dependent components. Say you have a bespoke component with data and labels in extra files:\n\nmyAwesomeApp.listener = function(component){\n\tif(component === 'bespokecomponent'){\n\t\tmyAwesomeApp.addComponent('bespokelabels');\n\t};\n\tif(component === 'bespokelabels'){\n\t\tmyAwesomeApp.addComponent('bespokedata');\n\t};\n\tif(component === 'bespokedata'){\n\t\tmyAwesomeApp,bespokecomponent.init();\n\t};\n};\nmyAwesomeApp.components.bespokecomponent = {\n\turl:'bespoke.js',\n\tloaded:false\n};\nmyAwesomeApp.components.bespokelabels = {\n\turl:'bespokelabels.js',\n\tloaded:false\n};\nmyAwesomeApp.components.bespokedata = {\n\turl:'bespokedata.js',\n\tloaded:false\n};\nmyAwesomeApp.addComponent('bespokecomponent');\n\nFollowing this practice you can write pretty complex apps and still have full control over what is available when. You can also extend this to allow for CSS files to be added on demand.\n\nInfluences\n\nIf you like this idea and wondered if someone already uses it, take a look at the Yahoo! User Interface library, and especially at the YAHOO_config option of the global YAHOO.js object.", "year": "2007", "author": "Christian Heilmann", "author_slug": "chrisheilmann", "published": "2007-12-18T00:00:00+00:00", "url": "https://24ways.org/2007/keeping-javascript-dependencies-at-bay/", "topic": "code"} {"rowid": 162, "title": "Conditional Love", "contents": "\u201cBrowser.\u201d The four-letter word of web design.\n\nI mean, let\u2019s face it: on the good days, when things just work in your target browsers, it\u2019s marvelous. The air smells sweeter, birds\u2019 songs sound more melodious, and both your design and your code are looking sharp.\n\nBut on the less-than-good days (which is, frankly, most of them), you\u2019re compelled to tie up all your browsers in a sack, heave them into the nearest river, and start designing all-imagemap websites. We all play favorites, after all: some will swear by Firefox, Opera fans are allegedly legion, and others still will frown upon anything less than the latest WebKit nightly.\n\nThankfully, we do have an out for those little inconsistencies that crop up when dealing with cross-browser testing: CSS patches.\n\nSpare the Rod, Hack the Browser\n\nBefore committing browsercide over some rendering bug, a designer will typically reach for a snippet of CSS fix the faulty browser. Historically referred to as \u201chacks,\u201d I prefer Dan Cederholm\u2019s more client-friendly alternative, \u201cpatches\u201d.\n\nBut whatever you call them, CSS patches all work along the same principle: supply the proper property value to the good browsers, while giving higher maintenance other browsers an incorrect value that their frustrating idiosyncratic rendering engine can understand.\n\nTraditionally, this has been done either by exploiting incomplete CSS support:\n\n#content {\n\theight: 1%;\t // Let's force hasLayout for old versions of IE.\n\tline-height: 1.6;\n\tpadding: 1em;\n}\nhtml>body #content {\n\theight: auto; // Modern browsers get a proper height value.\n}\n\nor by exploiting bugs in their rendering engine to deliver alternate style rules:\n\n#content p {\n\tfont-size: .8em;\n\t/* Hide from Mac IE5 \\*/\n\tfont-size: .9em;\n\t/* End hiding from Mac IE5 */\n}\n\nWe\u2019ve even used these exploits to serve up whole stylesheets altogether:\n\n@import url(\"core.css\");\n@media tty {\n\ti{content:\"\\\";/*\" \"*/}} @import 'windows-ie5.css'; /*\";}\n}/* */\n\nThe list goes on, and on, and on. For every browser, for every bug, there\u2019s a patch available to fix some rendering bug.\n\nBut after some time working with standards-based layouts, I\u2019ve found that CSS patches, as we\u2019ve traditionally used them, become increasingly difficult to maintain. As stylesheets are modified over the course of a site\u2019s lifetime, inline fixes we\u2019ve written may become obsolete, making them difficult to find, update, or prune out of our CSS. A good patch requires a constant gardener to ensure that it adds more than just bloat to a stylesheet, and inline patches can be very hard to weed out of a decently sized CSS file.\n\nGiving the Kids Separate Rooms\n\nSince I joined Airbag Industries earlier this year, every project we\u2019ve worked on has this in the head of its templates:\n\n\n\n\n\nThe first element is, simply enough, a link element that points to the project\u2019s main CSS file. No patches, no hacks: just pure, modern browser-friendly style rules. Which, nine times out of ten, will net you a design that looks like spilled eggnog in various versions of Internet Explorer.\n\nBut don\u2019t reach for the mulled wine quite yet. Immediately after, we\u2019ve got a brace of conditional comments wrapped around two other link elements. These odd-looking comments allow us to selectively serve up additional stylesheets just to the version of IE that needs them. We\u2019ve got one for IE 6 and below:\n\n\n\nAnd another for IE7 and above:\n\n\n\nMicrosoft\u2019s conditional comments aren\u2019t exactly new, but they can be a valuable alternative to cooking CSS patches directly into a master stylesheet. And though they\u2019re not a W3C-approved markup structure, I think they\u2019re just brilliant because they innovate within the spec: non-IE devices will assume that the comments are just that, and ignore the markup altogether.\n\nThis does, of course, mean that there\u2019s a little extra markup in the head of our documents. But this approach can seriously cut down on the unnecessary patches served up to the browsers that don\u2019t need them. Namely, we no longer have to write rules like this in our main stylesheet:\n\n#content {\n\theight: 1%;\t// Let's force hasLayout for old versions of IE.\n\tline-height: 1.6;\n\tpadding: 1em;\n}\nhtml>body #content {\n\theight: auto;\t// Modern browsers get a proper height value.\n}\n\nRather, we can simply write an un-patched rule in our core stylesheet:\n\n#content {\n\tline-height: 1.6;\n\tpadding: 1em;\n}\n\nAnd now, our patch for older versions of IE goes in\u2014you guessed it\u2014the stylesheet for older versions of IE:\n\n#content {\n\theight: 1%;\n}\n\nThe hasLayout patch is applied, our design\u2019s repaired, and\u2014most importantly\u2014the patch is only seen by the browser that needs it. The \u201cgood\u201d browsers don\u2019t have to incur any added stylesheet weight from our IE patches, and Internet Explorer gets the conditional love it deserves.\n\nMost importantly, this \u201ccompartmentalized\u201d approach to CSS patching makes it much easier for me to patch and maintain the fixes applied to a particular browser. If I need to track down a bug for IE7, I don\u2019t need to scroll through dozens or hundreds of rules in my core stylesheet: instead, I just open the considerably slimmer IE7-specific patch file, make my edits, and move right along.\n\nEven Good Children Misbehave\n\nWhile IE may occupy the bulk of our debugging time, there\u2019s no denying that other popular, modern browsers will occasionally disagree on how certain bits of CSS should be rendered. But without something as, well, pimp as conditional comments at our disposal, how do we bring the so-called \u201cgood browsers\u201d back in line with our design?\n\nAssuming you\u2019re loving the \u201cone patch file per browser\u201d model as much as I do, there\u2019s just one alternative: JavaScript.\n\nfunction isSaf() {\n\tvar isSaf = (document.childNodes && !document.all && !navigator.taintEnabled && !navigator.accentColorName) ? true : false;\n\treturn isSaf;\n}\nfunction isOp() {\n\tvar isOp = (window.opera) ? true : false;\n\treturn isOp;\n}\n\nInstead of relying on dotcom-era tactics of parsing the browser\u2019s user-agent string, we\u2019re testing here for support for various DOM objects, whose presence or absence we can use to reasonably infer the browser we\u2019re looking at. So running the isOp() function, for example, will test for Opera\u2019s proprietary window.opera object, and thereby accurately tell you if your user\u2019s running Norway\u2019s finest browser.\n\nWith scripts such as isOp() and isSaf() in place, you can then reasonably test which browser\u2019s viewing your content, and insert additional link elements as needed.\n\nfunction loadPatches(dir) {\n\tif (document.getElementsByTagName() && document.createElement()) {\n\t\tvar head = document.getElementsByTagName(\"head\")[0];\n\t\tif (head) {\n\t\t\tvar css = new Array();\n\t\t\tif (isSaf()) {\n\t\t\t\tcss.push(\"saf.css\");\n\t\t\t} else if (isOp()) {\n\t\t\t\tcss.push(\"opera.css\");\n\t\t\t}\n\t\t\tif (css.length) {\n\t\t\t\tvar link = document.createElement(\"link\");\n\t\t\t\tlink.setAttribute(\"rel\", \"stylesheet\");\n\t\t\t\tlink.setAttribute(\"type\", \"text/css\");\n\t\t\t\tlink.setAttribute(\"media\", \"screen, projection\");\n\t\t\t\tfor (var i = 0; i < css.length; i++) {\n\t\t\t\t\tvar tag = link.cloneNode(true);\n\t\t\t\t\ttag.setAttribute(\"href\", dir + css[0]);\n\t\t\t\t\thead.appendChild(tag);\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t}\n}\n\nHere, we\u2019re testing the results of isSaf() and isOp(), one after the other. For each function that returns true, then the name of a new stylesheet is added to the oh-so-cleverly named css array. Then, for each entry in css, we create a new link element, point it at our patch file, and insert it into the head of our template.\n\nFire it up using your favorite onload or DOMContentLoaded function, and you\u2019re good to go.\n\nScripteat Emptor\n\nAt this point, some of the audience\u2019s more conscientious \u2018scripters may be preparing to lob figgy pudding at this author\u2019s head. And that\u2019s perfectly understandable; relying on JavaScript to patch CSS chafes a bit against the normally clean separation we have between our pages\u2019 content, presentation, and behavior layers.\n\nAnd beyond the philosophical concerns, this approach comes with a few technical caveats attached:\n\nBrowser detection? So un-133t.\n\nBrowser detection is not something I\u2019d typically recommend. Whenever possible, a proper DOM script should check for the support of a given object or method, rather than the device with which your users view your content.\n\nIt\u2019s JavaScript, so don\u2019t count on it being available.\n\nAccording to one site, roughly four percent of Internet users don\u2019t have JavaScript enabled. Your site\u2019s stats might be higher or lower than this number, but still: don\u2019t expect that every member of your audience will see these additional stylesheets, and ensure that your content\u2019s still accessible with JS turned off.\n\nBe a constant gardener.\n\nThe sample isSaf() and isOp() functions I\u2019ve written will tell you if the user\u2019s browser is Safari or Opera. As a result, stylesheets written to patch issues in an old browser may break when later releases repair the relevant CSS bugs.\n\nYou can, of course, add logic to these simple little scripts to serve up version-specific stylesheets, but that way madness may lie. In any event, test your work vigorously, and keep testing it when new versions of the targeted browsers come out. Make sure that a patch written today doesn\u2019t become a bug tomorrow.\n\nPatching Firefox, Opera, and Safari isn\u2019t something I\u2019ve had to do frequently: still, there have been occasions where the above script\u2019s come in handy. Between conditional comments, careful CSS auditing, and some judicious JavaScript, browser-based bugs can be handled with near-surgical precision.\n\nSo pass the \u2018nog. It\u2019s patchin\u2019 time.", "year": "2007", "author": "Ethan Marcotte", "author_slug": "ethanmarcotte", "published": "2007-12-15T00:00:00+00:00", "url": "https://24ways.org/2007/conditional-love/", "topic": "code"} {"rowid": 163, "title": "Get To Grips with Slippy Maps", "contents": "Online mapping has definitely hit mainstream. Google Maps made \u2018slippy maps\u2019 popular and made it easy for any developer to quickly add a dynamic map to his or her website. You can now find maps for store locations, friends nearby, upcoming events, and embedded in blogs. \n\nIn this tutorial we\u2019ll show you how to easily add a map to your site using the Mapstraction mapping library. There are many map providers available to choose from, each with slightly different functionality, design, and terms of service. Mapstraction makes deciding which provider to use easy by allowing you to write your mapping code once, and then easily switch providers.\n\nAssemble the pieces\n\nUtilizing any of the mapping library typically consists of similar overall steps:\n\n\n\tCreate an HTML div to hold the map\n\tInclude the Javascript libraries\n\tCreate the Javascript Map element\n\tSet the initial map center and zoom level\n\tAdd markers, lines, overlays and more\n\n\nCreate the Map Div\n\nThe HTML div is where the map will actually show up on your page. It needs to have a unique id, because we\u2019ll refer to that later to actually put the map here. This also lets you have multiple maps on a page, by creating individual divs and Javascript map elements. The size of the div also sets the height and width of the map. You set the size using CSS, either inline with the element, or via a CSS reference to the element id or class. For this example, we\u2019ll use inline styling.\n\n
\n\nInclude Javascript libraries\n\nA mapping library is like any Javascript library. You need to include the library in your page before you use the methods of that library. For our tutorial, we\u2019ll need to include at least two libraries: Mapstraction, and the mapping API(s) we want to display. Our first example we\u2019ll use the ubiquitous Google Maps library. However, you can just as easily include Yahoo, MapQuest, or any of the other supported libraries.\n\nAnother important aspect of the mapping libraries is that many of them require an API key. You will need to agree to the terms of service, and get an API key these.\n\n\n\n\nCreate the Map\n\nGreat, we\u2019ve now put in all the pieces we need to start actually creating our map. This is as simple as creating a new Mapstraction object with the id of the HTML div we created earlier, and the name of the mapping provider we want to use for this map. \n\nWith several of the mapping libraries you will need to set the map center and zoom level before the map will appear. The map centering actually triggers the initialization of the map. \n\nvar mapstraction = new Mapstraction('map','google');\nvar myPoint = new LatLonPoint(37.404,-122.008);\nmapstraction.setCenterAndZoom(myPoint, 10);\n\nA note about zoom levels. The setCenterAndZoom function takes two parameters, the center as a LatLonPoint, and a zoom level that has been defined by mapping libraries. The current usage is for zoom level 1 to be \u201czoomed out\u201d, or view the entire earth \u2013 and increasing the zoom level as you zoom in. Typically 17 is the maximum zoom, which is about the size of a house. \n\nDifferent mapping providers have different quality of zoomed in maps over different parts of the world. This is a perfect reason why using a library like Mapstraction is very useful, because you can quickly change mapping providers to accommodate users in areas that have bad coverage with some maps. \n\nTo switch providers, you just need to include the Javascript library, and then change the second parameter in the Mapstraction creation. Or, you can call the switch method to dynamically switch the provider.\n\nSo for Yahoo Maps (demo):\n\nvar mapstraction = new Mapstraction('map','yahoo');\n\nor Microsoft Maps (demo):\n\nvar mapstraction = new Mapstraction('map','microsoft');\n\nwant a 3D globe in your browser? try FreeEarth (demo):\n\nvar mapstraction = new Mapstraction('map','freeearth');\n\nor even OpenStreetMap (free your data!) (demo):\n\nvar mapstraction = new Mapstraction('map','openstreetmap');\n\nVisit the Mapstraction multiple map demo page for an example of how easy it is to have many maps on your page, each with a different provider. \n\nAdding Markers\n\nWhile adding your first map is fun, and you can probably spend hours just sliding around, the point of adding a map to your site is usually to show the location of something. So now you want to add some markers. There are a couple of ways to add to your map.\n\nThe simplest is directly creating markers. You could either hard code this into a rather static page, or dynamically generate these using whatever tools your site is built on.\n\nvar marker = new Marker( new LatLonPoint(37.404,-122.008) );\nmarker.setInfoBubble(\"It's easy to add maps to your site\");\nmapstraction.addMarker( marker );\n\nThere is a lot more you can do with markers, including changing the icon, adding timestamps, automatically opening the bubble, or making them draggable. \n\nWhile it is straight-forward to create markers one by one, there is a much easier way to create a large set of markers. And chances are, you can make it very easy by extending some data you already are sharing: RSS. \n\nSpecifically, using GeoRSS you can easily add a large set of markers directly to a map. GeoRSS is a community built standard (like Microformats) that added geographic markup to RSS and Atom entries. It\u2019s as simple as adding 42 -83 to your feeds to share items via GeoRSS. Once you\u2019ve done that, you can add that feed as an \u2018overlay\u2019 to your map using the function:\n\nmapstraction.addOverlay(\"http://api.flickr.com/services/feeds/groups_pool.gne?id=322338@N20&format=rss_200&georss=1\");\n\nMapstraction also supports KML for many of the mapping providers. So it\u2019s easy to add various data sources together with your own data. Check out Mapufacture for a growing index of available GeoRSS feeds and KML documents. \n\nPlay with your new toys\n\nMapstraction offers a lot more functionality you can utilize for demonstrating a lot of geographic data on your website. It also includes geocoding and routing abstraction layers for making sure your users know where to go. You can see more on the Mapstraction website: http://mapstraction.com.", "year": "2007", "author": "Andrew Turner", "author_slug": "andrewturner", "published": "2007-12-02T00:00:00+00:00", "url": "https://24ways.org/2007/get-to-grips-with-slippy-maps/", "topic": "code"} {"rowid": 164, "title": "My Other Christmas Present Is a Definition List", "contents": "A note from the editors: readers should note that the HTML5 redefinition of definition lists has come to pass and is now \u00e0 la mode.\n \n \n \n Last year, I looked at how the markup for tag clouds was generally terrible. I thought this year I would look not at a method of marking up a common module, but instead just at a simple part of HTML and how it generally gets abused.\n\nNo, not tables. Definition lists. Ah, definition lists. Often used but rarely understood.\n\nExamining the definition of definitions\n\nTo start with, let\u2019s see what the HTML spec has to say about them.\n\n\n\tDefinition lists vary only slightly from other types of lists in that list items consist of two parts: a term and a description.\n\n\nThe canonical example of a definition list is a dictionary. Words can have multiple descriptions (even the word definition has at least five). Also, many terms can share a single definition (for example, the word colour can also be spelt color, but they have the same definition).\n\nExcellent, we can all grasp that. But it very quickly starts to fall apart. Even in the HTML specification the definition list is mis-used.\n\n\n\tAnother application of DL, for example, is for marking up dialogues, with each DT naming a speaker, and each DD containing his or her words.\n\n\nWrong. Completely and utterly wrong. This is the biggest flaw in the HTML spec, along with dropping support for the start attribute on ordered lists. \u201cWhy?\u201d, you may ask. Let me give you an example from Romeo and Juliet, act 2, scene 2.\n\n
Juliet
\n\t
Romeo!
\n
Romeo
\n\t
My niesse?
\n
Juliet
\n\t
At what o'clock tomorrow shall I send to thee?
\n
Romeo
\n\t
At the hour of nine.
\n\nNow, the problem here is that a given definition can have multiple descriptions (the DD). Really the dialog \u201cdescriptions\u201d should be rolled up under the terms, like so:\n\n
Juliet
\n\t
Romeo!
\n\t
At what o'clock tomorrow shall I send to thee?
\n
Romeo
\n\t
My niesse?
\n\t
At the hour of nine.
\n\nSuddenly the play won\u2019t make anywhere near as much sense. (If it\u2019s anything, the correct markup for a play is an ordered list of CITE and BLOCKQUOTE elements.)\n\nThis is the first part of the problem. That simple example has turned definition lists in everyone\u2019s mind from pure definitions to more along the lines of a list with pre-configured heading(s) and text(s).\n\nScreen reader, enter stage left.\n\nIn many screen readers, a simple definition list would be read out as \u201cdefinition term equals definition description\u201d. So in our play excerpt, Juliet equals Romeo! That\u2019s not right, either. But this also leads a lot of people astray with definition lists to believing that they are useful for key/value pairs.\n\nBehaviour and convention\n\nThe WHAT-WG have noticed the common mis-use of the DL, and have codified it into the new spec. In the HTML5 draft, a definition list is no longer a definition list.\n\n\n\tThe dl element introduces an unordered association list consisting of zero or more name-value groups (a description list). Each group must consist of one or more names (dt elements) followed by one or more values (dd elements).\n\n\nThey also note that the \u201cdl element is inappropriate for marking up dialogue, since dialogue is ordered\u201d. So for that example they have created a DIALOG (sic) element.\n\nStrange, then, that they keep DL as-is but instead refer to it an \u201cassociation list\u201d. They have not created a new AL element, and kept DL for the original purpose. They have chosen not to correct the usage or to create a new opportunity for increased specificity in our HTML, but to \u201cpave the cowpath\u201d of convention.\n\nHow to use a definition list\n\nGiven that everyone else is using a DL incorrectly, should we? Well, if they all jumped off a bridge, would you too? No, of course you wouldn\u2019t. We don\u2019t have HTML5 yet, so we\u2019re stuck with the existing semantics of HTML4 and XHTML1. Which means that:\n\n\n\tListing dialogue is not defining anything.\n\tListing the attributes of a piece of hardware (resolution = 1600\u00d71200) is illustrating sample values, not defining anything (however, stating what \u2018resolution\u2019 actually means in this context would be a definition).\n\tListing the cast and crew of a given movie is not defining the people involved in making movies. (Stuart Gordon may have been the director of Space Truckers, but that by no means makes him the true definition of a director.)\n\tA menu of navigation items is simply a nested ordered or unordered list of links, not a definition list.\n\tApplying styling handles to form labels and elements is not a good use for a definition list.\n\n\nAnd so on.\n\nLiving by the specification, a definition list should be used for term definitions \u2013 glossaries, lexicons and dictionaries \u2013 only.\n\nAnything else is a crime against markup.", "year": "2007", "author": "Mark Norman Francis", "author_slug": "marknormanfrancis", "published": "2007-12-05T00:00:00+00:00", "url": "https://24ways.org/2007/my-other-christmas-present-is-a-definition-list/", "topic": "code"} {"rowid": 165, "title": "Transparent PNGs in Internet Explorer 6", "contents": "Newer breeds of browser such as Firefox and Safari have offered support for PNG images with full alpha channel transparency for a few years. With the use of hacks, support has been available in Internet Explorer 5.5 and 6, but the hacks are non-ideal and have been tricky to use. With IE7 winning masses of users from earlier versions over the last year, full PNG alpha-channel transparency is becoming more of a reality for day-to-day use.\n\nHowever, there are still numbers of IE6 users out there who we can\u2019t leave out in the cold this Christmas, so in this article I\u2019m going to look what we can do to support IE6 users whilst taking full advantage of transparency for the majority of a site\u2019s visitors.\n\nSo what\u2019s alpha channel transparency?\n\nCast your minds back to the Ghost of Christmas Past, the humble GIF. Images in GIF format offer transparency, but that transparency is either on or off for any given pixel. Each pixel\u2019s either fully transparent, or a solid colour. In GIF, transparency is effectively just a special colour you can chose for a pixel.\n\nThe PNG format tackles the problem rather differently. As well as having any colour you chose, each pixel also carries a separate channel of information detailing how transparent it is. This alpha channel enables a pixel to be fully transparent, fully opaque, or critically, any step in between.\n\nThis enables designers to produce images that can have, for example, soft edges without any of the \u2018halo effect\u2019 traditionally associated with GIF transparency. If you\u2019ve ever worked on a site that has different colour schemes and therefore requires multiple versions of each graphic against a different colour, you\u2019ll immediately see the benefit. \n\nWhat\u2019s perhaps more interesting than that, however, is the extra creative freedom this gives designers in creating beautiful sites that can remain web-like in their ability to adjust, scale and reflow.\n\nThe Internet Explorer problem\n\nUp until IE7, there has been no fully native support for PNG alpha channel transparency in Internet Explorer. However, since IE5.5 there has been some support in the form of proprietary filter called the AlphaImageLoader. Internet Explorer filters can be applied directly in your CSS (for both inline and background images), or by setting the same CSS property with JavaScript. \n\nCSS:\n\nimg {\n\tfilter: progid:DXImageTransform.Microsoft.AlphaImageLoader(...);\n}\n\nJavaScript:\n\nimg.style.filter = \"progid:DXImageTransform.Microsoft.AlphaImageLoader(...)\";\n\nThat may sound like a problem solved, but all is not as it may appear. Firstly, as you may realise, there\u2019s no CSS property called filter in the W3C CSS spec. It\u2019s a proprietary extension added by Microsoft that could potentially cause other browsers to reject your entire CSS rule. \n\nSecondly, AlphaImageLoader does not magically add full PNG transparency support so that a PNG in the page will just start working. Instead, when applied to an element in the page, it draws a new rendering surface in the same space that element occupies and loads a PNG into it. If that sounds weird, it\u2019s because that\u2019s precisely what it is. However, by and large the result is that PNGs with an alpha channel can be accommodated.\n\nThe pitfalls\n\nSo, whilst support for PNG transparency in IE5.5 and 6 is possible, it\u2019s not without its problems.\n\nBackground images cannot be positioned or repeated\n\nThe AlphaImageLoader does work for background images, but only for the simplest of cases. If your design requires the image to be tiled (background-repeat) or positioned (background-position) you\u2019re out of luck. The AlphaImageLoader allows you to set a sizingMethod to either crop the image (if necessary) or to scale it to fit. Not massively useful, but something at least.\n\nDelayed loading and resource use\n\nThe AlphaImageLoader can be quite slow to load, and appears to consume more resources than a standard image when applied. Typically, you\u2019d need to add thousands of GIFs or JPEGs to a page before you saw any noticeable impact on the browser, but with the AlphaImageLoader filter applied Internet Explorer can become sluggish after just a handful of alpha channel PNGs.\n\nThe other noticeable effect is that as more instances of the AlphaImageLoader are applied, the longer it takes to render the PNGs with their transparency. The user sees the PNG load in its original non-supported state (with black or grey areas where transparency should be) before one by one the filter kicks in and makes them properly transparent.\n\nBoth the issue of sluggish behaviour and delayed load only really manifest themselves with volume and size of image. Use just a couple of instances and it\u2019s fine, but be careful adding more than five or six. As ever, test, test, test.\n\nLinks become unclickable, forms unfocusable \n\nThis is a big one. There\u2019s a bug/weirdness with AlphaImageLoader that sometimes prevents interaction with links and forms when a PNG background image is used. This is sometimes reported as a z-index issue, but I don\u2019t believe it is. Rather, it\u2019s an artefact of that weird way the filter gets applied to the document almost outside of the normal render process. \n\nOften this can be solved by giving the links or form elements hasLayout using position: relative; where possible. However, this doesn\u2019t always work and the non-interaction problem cannot always be solved. You may find yourself having to go back to the drawing board.\n\nSidestepping the danger zones\n\nFrankly, it\u2019s pretty bad news if you design a site, have that design signed off by your client, build it and then find out only at the end (because you don\u2019t know what might trigger a problem) that your search field can\u2019t be focused in IE6. That\u2019s an absolute nightmare, and whilst it\u2019s not likely to happen, it\u2019s possible that it might. It\u2019s happened to me. So what can you do?\n\nThe best approach I\u2019ve found to this scenario is\n\n\n\tIsolate the PNG or PNGs that are causing the problem. Step through the PNGs in your page, commenting them out one by one and retesting. Typically it\u2019ll be the nearest PNG to the problem, so try there first. Keep going until you can click your links or focus your form fields.\n\tThis is where you really need luck on your side, because you\u2019re going to have to fake it. This will depend on the design of the site, but some way or other create a replacement GIF or JPEG image that will give you an acceptable result. Then use conditional comments to serve that image to only users of IE older than version 7.\n\n\nA hack, you say? Well, you started it chum.\n\nApplying AlphaImageLoader\n\nBecause the filter property is invalid CSS, the safest pragmatic approach is to apply it selectively with JavaScript for only Internet Explorer versions 5.5 and 6. This helps ensure that by default you\u2019re serving standard CSS to browsers that support both the CSS and PNG standards correct, and then selectively patching up only the browsers that need it. \n\nSeveral years ago, Aaron Boodman wrote and released a script called sleight for doing just that. However, sleight dealt only with images in the page, and not background images applied with CSS. Building on top of Aaron\u2019s work, I hacked sleight and came up with bgsleight for applying the filter to background images instead. That was in 2003, and over the years I\u2019ve made a couple of improvements here and there to keep it ticking over and to resolve conflicts between sleight and bgsleight when used together. However, with alpha channel PNGs becoming much more widespread, it\u2019s time for a new version.\n\nIntroducing SuperSleight\n\nSuperSleight adds a number of new and useful features that have come from the day-to-day needs of working with PNGs.\n\n\n\tWorks with both inline and background images, replacing the need for both sleight and bgsleight\n\tWill automatically apply position: relative to links and form fields if they don\u2019t already have position set. (Can be disabled.)\n\tCan be run on the entire document, or just a selected part where you know the PNGs are. This is better for performance.\n\tDetects background images set to no-repeat and sets the scaleMode to crop rather than scale.\n\tCan be re-applied by any other JavaScript in the page \u2013 useful if new content has been loaded by an Ajax request.\n\n\n Download SuperSleight \n\nImplementation\n\nGetting SuperSleight running on a page is quite straightforward, you just need to link the supplied JavaScript file (or the minified version if you prefer) into your document inside conditional comments so that it is delivered to only Internet Explorer 6 or older.\n\n\n\nSupplied with the JavaScript is a simple transparent GIF file. The script replaces the existing PNG with this before re-layering the PNG over the top using AlphaImageLoaded. You can change the name or path of the image in the top of the JavaScript file, where you\u2019ll also find the option to turn off the adding of position: relative to links and fields if you don\u2019t want that.\n\nThe script is kicked off with a call to supersleight.init() at the bottom. The scope of the script can be limited to just one part of the page by passing an ID of an element to supersleight.limitTo(). And that\u2019s all there is to it.\n\nUpdate March 2008: a version of this script as a jQuery plugin is also now available.", "year": "2007", "author": "Drew McLellan", "author_slug": "drewmclellan", "published": "2007-12-01T00:00:00+00:00", "url": "https://24ways.org/2007/supersleight-transparent-png-in-ie6/", "topic": "code"} {"rowid": 168, "title": "Unobtrusively Mapping Microformats with jQuery", "contents": "Microformats are everywhere. You can\u2019t shake an electronic stick these days without accidentally poking a microformat-enabled site, and many developers use microformats as a matter of course. And why not? After all, why invent your own class names when you can re-use pre-defined ones that give your site extra functionality for free?\n\nNevertheless, while it\u2019s good to know that users of tools such as Tails and Operator will derive added value from your shiny semantics, it\u2019s nice to be able to reuse that effort in your own code.\n\nWe\u2019re going to build a map of some of my favourite restaurants in Brighton. Fitting with the principles of unobtrusive JavaScript, we\u2019ll start with a semantically marked up list of restaurants, then use JavaScript to add the map, look up the restaurant locations and plot them as markers.\n\nWe\u2019ll be using a couple of powerful tools. The first is jQuery, a JavaScript library that is ideally suited for unobtrusive scripting. jQuery allows us to manipulate elements on the page based on their CSS selector, which makes it easy to extract information from microformats.\n\nThe second is Mapstraction, introduced here by Andrew Turner a few days ago. We\u2019ll be using Google Maps in the background, but Mapstraction makes it easy to change to a different provider if we want to later.\n\nGetting Started\n\nWe\u2019ll start off with a simple collection of microformatted restaurant details, representing my seven favourite restaurants in Brighton. The full, unstyled list can be seen in restaurants-plain.html. Each restaurant listing looks like this:\n\n
  • \n\t

    Riddle & Finns

    \n\t
    \n\t\t

    12b Meeting House Lane

    \n\t\t

    Brighton, UK

    \n\t\t

    BN1 1HB

    \n\t
    \n\t

    Telephone: +44 (0)1273 323 008

    \n\t

    E-mail: info@riddleandfinns.co.uk

    \n
  • \n\nSince we\u2019re dealing with a list of restaurants, each hCard is marked up inside a list item. Each restaurant is an organisation; we signify this by placing the classes fn and org on the element surrounding the restaurant\u2019s name (according to the hCard spec, setting both fn and org to the same value signifies that the hCard represents an organisation rather than a person).\n\nThe address information itself is contained within a div of class adr. Note that the HTML
    element is not suitable here for two reasons: firstly, it is intended to mark up contact details for the current document rather than generic addresses; secondly, address is an inline element and as such cannot contain the paragraphs elements used here for the address information.\n\nA nice thing about microformats is that they provide us with automatic hooks for our styling. For the moment we\u2019ll just tidy up the whitespace a bit; for more advanced style tips consult John Allsop\u2019s guide from 24 ways 2006.\n\n.vcard p {\n\tmargin: 0;\n}\n.adr {\n\tmargin-bottom: 0.5em;\n}\n\nTo plot the restaurants on a map we\u2019ll need latitude and longitude for each one. We can find this out from their address using geocoding. Most mapping APIs include support for geocoding, which means we can pass the API an address and get back a latitude/longitude point. Mapstraction provides an abstraction layer around these APIs which can be included using the following script tag:\n\n\n\nWhile we\u2019re at it, let\u2019s pull in the other external scripts we\u2019ll be using:\n\n\n\n\n\n\nThat\u2019s everything set up: let\u2019s write some JavaScript!\n\nIn jQuery, almost every operation starts with a call to the jQuery function. The function simulates method overloading to behave in different ways depending on the arguments passed to it. When writing unobtrusive JavaScript it\u2019s important to set up code to execute when the page has loaded to the point that the DOM is available to be manipulated. To do this with jQuery, pass a callback function to the jQuery function itself:\n\njQuery(function() {\n\t// This code will be executed when the DOM is ready\n});\n\nInitialising the map\n\nThe first thing we need to do is initialise our map. Mapstraction needs a div with an explicit width, height and ID to show it where to put the map. Our document doesn\u2019t currently include this markup, but we can insert it with a single line of jQuery code:\n\njQuery(function() {\n\t// First create a div to host the map\n\tvar themap = jQuery('
    ').css({\n\t\t'width': '90%',\n\t\t'height': '400px'\n\t}).insertBefore('ul.restaurants');\n});\n\nWhile this is technically just a single line of JavaScript (with line-breaks added for readability) it\u2019s actually doing quite a lot of work. Let\u2019s break it down in to steps:\n\nvar themap = jQuery('
    ')\n\nHere\u2019s jQuery\u2019s method overloading in action: if you pass it a string that starts with a < it assumes that you wish to create a new HTML element. This provides us with a handy shortcut for the more verbose DOM equivalent:\n\nvar themap = document.createElement('div');\nthemap.id = 'themap';\n\nNext we want to apply some CSS rules to the element. jQuery supports chaining, which means we can continue to call methods on the object returned by jQuery or any of its methods:\n\nvar themap = jQuery('
    ').css({\n\t'width': '90%',\n\t'height': '400px'\n})\n\nFinally, we need to insert our new HTML element in to the page. jQuery provides a number of methods for element insertion, but in this case we want to position it directly before the