[{"rowid": 121, "title": "Hide And Seek in The Head", "contents": "If you want your JavaScript-enhanced pages to remain accessible and understandable to scripted and noscript users alike, you have to think before you code. Which functionalities are required (ie. should work without JavaScript)? Which ones are merely nice-to-have (ie. can be scripted)? You should only start creating the site when you\u2019ve taken these decisions.\n\nSpecial HTML elements\n\nOnce you have a clear idea of what will work with and without JavaScript, you\u2019ll likely find that you need a few HTML elements for the noscript version only.\n\nTake this example: A form has a nifty bit of Ajax that automatically and silently sends a request once the user enters something in a form field. However, in order to preserve accessibility, the user should also be able to submit the form normally. So the form should have a submit button in noscript browsers, but not when the browser supports sufficient JavaScript.\n\nSince the button is meant for noscript browsers, it must be hard-coded in the HTML:\n\n\n\nWhen JavaScript is supported, it should be removed:\n\nvar checkJS = [check JavaScript support];\nwindow.onload = function () {\n\tif (!checkJS) return;\n\tdocument.getElementById('noScriptButton').style.display = 'none';\n}\n\nProblem: the load event\n\nAlthough this will likely work fine in your testing environment, it\u2019s not completely correct. What if a user with a modern, JavaScript-capable browser visits your page, but has to wait for a huge graphic to load? The load event fires only after all assets, including images, have been loaded. So this user will first see a submit button, but then all of a sudden it\u2019s removed. That\u2019s potentially confusing.\n\nFortunately there\u2019s a simple solution: play a bit of hide and seek in the :\n\nvar checkJS = [check JavaScript support];\nif (checkJS) {\n\tdocument.write('');\n}\n\nFirst, check if the browser supports enough JavaScript. If it does, document.write an extra \n\nSo we end up with a nice simple to understand but also quick to write XSL which can be used on ATOM Flickr feeds and ATOM News feeds. With a little playing around with XSL, you can make XML beautiful again.\n\nAll the files can be found in the zip file (14k)", "year": "2006", "author": "Ian Forrester", "author_slug": "ianforrester", "published": "2006-12-07T00:00:00+00:00", "url": "https://24ways.org/2006/beautiful-xml-with-xsl/", "topic": "code"}, {"rowid": 138, "title": "Rounded Corner Boxes the CSS3 Way", "contents": "If you\u2019ve been doing CSS for a while you\u2019ll know that there are approximately 3,762 ways to create a rounded corner box. The simplest techniques rely on the addition of extra mark-up directly to your page, while the more complicated ones add the mark-up though DOM manipulation. While these techniques are all very interesting, they do seem somewhat of a kludge. The goal of CSS is to separate structure from presentation, yet here we are adding superfluous mark-up to our code in order to create a visual effect. The reason we are doing this is simple. CSS2.1 only allows a single background image per element.\n\nThankfully this looks set to change with the addition of multiple background images into the CSS3 specification. With CSS3 you\u2019ll be able to add not one, not four, but eight background images to a single element. This means you\u2019ll be able to create all kinds of interesting effects without the need of those additional elements.\n\nWhile the CSS working group still seem to be arguing over the exact syntax, Dave Hyatt went ahead and implemented the currently suggested mechanism into Safari. The technique is fiendishly simple, and I think we\u2019ll all be a lot better off once the W3C stop arguing over the details and allow browser vendors to get on and provide the tools we need to build better websites.\n\nTo create a CSS3 rounded corner box, simply start with your box element and apply your 4 corner images, separated by commas.\n\n.box {\n\tbackground-image: url(top-left.gif), url(top-right.gif), url(bottom-left.gif), url(bottom-right.gif);\n}\n\nWe don\u2019t want these background images to repeat, which is the normal behaviour, so lets set all their background-repeat properties to no-repeat.\n\n.box {\n\tbackground-image: url(top-left.gif), url(top-right.gif), url(bottom-left.gif), url(bottom-right.gif);\n\tbackground-repeat: no-repeat, no-repeat, no-repeat, no-repeat;\n}\n\nLastly, we need to define the positioning of each corner image.\n\n.box {\n\tbackground-image: url(top-left.gif), url(top-right.gif), url(bottom-left.gif), url(bottom-right.gif);\n\tbackground-repeat: no-repeat, no-repeat, no-repeat, no-repeat;\n\tbackground-position: top left, top right, bottom left, bottom right;\n}\n\nAnd there we have it, a simple rounded corner box with no additional mark-up.\n\nAs well as using multiple background images, CSS3 also has the ability to create rounded corners without the need of any images at all. You can do this by setting the border-radius property to your desired value as seen in the next example.\n\n.box {\n\tborder-radius: 1.6em;\n}\n\nThis technique currently works in Firefox/Camino and creates a nice, if somewhat jagged rounded corner. If you want to create a box that works in both Mozilla and WebKit based browsers, why not combine both techniques and see what happens.", "year": "2006", "author": "Andy Budd", "author_slug": "andybudd", "published": "2006-12-04T00:00:00+00:00", "url": "https://24ways.org/2006/rounded-corner-boxes-the-css3-way/", "topic": "code"}, {"rowid": 139, "title": "Flickr Photos On Demand with getFlickr", "contents": "In case you don\u2019t know it yet, Flickr is great. It is a lot of fun to upload, tag and caption photos and it is really handy to get a vast network of contacts through it. \n\nUsing Flickr photos outside of it is a bit of a problem though. There is a Flickr API, and you can get almost every page as an RSS feed, but in general it is a bit tricky to use Flickr photos inside your blog posts or web sites. You might not want to get into the whole API game or use a server side proxy script as you cannot retrieve RSS with Ajax because of the cross-domain security settings.\n\nHowever, Flickr also provides an undocumented JSON output, that can be used to hack your own solutions in JavaScript without having to use a server side script.\n\n\n\tIf you enter the URL http://flickr.com/photos/tags/panda you get to the flickr page with photos tagged \u201cpanda\u201d.\n\tIf you enter the URL http://api.flickr.com/services/feeds/photos_public.gne?tags=panda&format=rss_200 you get the same page as an RSS feed.\n\tIf you enter the URL http://api.flickr.com/services/feeds/photos_public.gne?tags=panda&format=json you get a JavaScript function called jsonFlickrFeed with a parameter that contains the same data in JSON format\n\n\nYou can use this to easily hack together your own output by just providing a function with the same name. I wanted to make it easier for you, which is why I created the helper getFlickr for you to download and use.\n\ngetFlickr for Non-Scripters\n\nSimply include the javascript file getflickr.js and the style getflickr.css in the head of your document:\n\n\n\n\nOnce this is done you can add links to Flickr pages anywhere in your document, and when you give them the CSS class getflickrphotos they get turned into gallery links. When a visitor clicks these links they turn into loading messages and show a \u201cpopup\u201d gallery with the connected photos once they were loaded. As the JSON returned is very small it won\u2019t take long. You can close the gallery, or click any of the thumbnails to view a photo. Clicking the photo makes it disappear and go back to the thumbnails.\n\nCheck out the example page and click the different gallery links to see the results.\n\nNotice that getFlickr works with Unobtrusive JavaScript as when scripting is disabled the links still get to the photos on Flickr.\n\ngetFlickr for JavaScript Hackers\n\nIf you want to use getFlickr with your own JavaScripts you can use its main method leech():\n\ngetFlickr.leech(sTag, sCallback);\n\n \n\tsTag\n\tthe tag you are looking for\n\tsCallback\n\tan optional function to call when the data was retrieved.\n \n\nAfter you called the leech() method you have two strings to use:\n\n \n\tgetFlickr.html[sTag]\n\tcontains an HTML list (without the outer UL element) of all the images linked to the correct pages at flickr. The images are the medium size, you can easily change that by replacing _m.jpg with _s.jpg for thumbnails.\n\tgetFlickr.tags[sTag]\n\tcontains a string of all the other tags flickr users added with the tag you searched for(space separated)\n \n\nYou can call getFlickr.leech() several times when the page has loaded to cache several result feeds before the page gets loaded. This\u2019ll make the photos quicker for the end user to show up. If you want to offer a form for people to search for flickr photos and display them immediately you can use the following HTML:\n\n
\n \n \n \n

Tags:

\n

Photos:

\n
\n\nAll the JavaScript you\u2019ll need (for a basic display) is this:\n\nfunction populate(){\n var tag = document.getElementById('tag').value;\n document.getElementById('photos').innerHTML = getFlickr.html[tag].replace(/_m\\.jpg/g,'_s.jpg');\n document.getElementById('tags').innerHTML = getFlickr.tags[tag];\n return false;\n}\n\nEasy as pie, enjoy!\n\nCheck out the example page and try the form to see the results.", "year": "2006", "author": "Christian Heilmann", "author_slug": "chrisheilmann", "published": "2006-12-03T00:00:00+00:00", "url": "https://24ways.org/2006/flickr-photos-on-demand/", "topic": "code"}, {"rowid": 143, "title": "Marking Up a Tag Cloud", "contents": "Everyone\u2019s doing it. \n\nThe problem is, everyone\u2019s doing it wrong. \n\nHarsh words, you might think. But the crimes against decent markup are legion in this area. You see, I\u2019m something of a markup and semantics junkie. So I\u2019m going to analyse some of the more well-known tag clouds on the internet, explain what\u2019s wrong, and then show you one way to do it better. \n\ndel.icio.us \n\nI think the first ever tag cloud I saw was on del.icio.us. Here\u2019s how they mark it up. \n\n
\n\t.net\n\tadvertising\n\tajax\n\t...\n
\n\nUnfortunately, that is one of the worst examples of tag cloud markup I have ever seen. The page states that a tag cloud is a list of tags where size reflects popularity. However, despite describing it in this way to the human readers, the page\u2019s author hasn\u2019t described it that way in the markup. It isn\u2019t a list of tags, just a bunch of anchors in a
. This is also inaccessible because a screenreader will not pause between adjacent links, and in some configurations will not announce the individual links, but rather all of the tags will be read as just one link containing a whole bunch of words. Markup crime number one. \n\nFlickr \n\nAh, Flickr. The darling photo sharing site of the internet, and the biggest blind spot in every standardista\u2019s vision. Forgive it for having atrocious markup and sometimes confusing UI because it\u2019s just so much damn fun to use. Let\u2019s see what they do. \n\n

\n\t\u00a006\u00a0\n\t\u00a0africa\u00a0\n\t\u00a0amsterdam\u00a0\n\t...\n

\n\nAgain we have a simple collection of anchors like del.icio.us, only this time in a paragraph. But rather than using a class to represent the size of the tag they use an inline style. An inline style using a pixel-based font size. That\u2019s so far away from the goal of separating style from content, they might as well use a tag. You could theoretically parse that to extract the information, but you have more work to guess what the pixel sizes represent. Markup crime number two (and extra jail time for using non-breaking spaces purely for visual spacing purposes.)\n\nTechnorati \n\nAh, now. Here, you\u2019d expect something decent. After all, the Overlord of microformats and King of Semantics Tantek \u00c7elik works there. Surely we\u2019ll see something decent here? \n\n
    \n\t
  1. Britney Spears
    2. \n\t
  2. Bush
    3. \n\t
  3. Christmas
    4. \n\t...\n\t
  4. SEO
    5. \n\t
  5. Shopping
    6. \n\t...\n
\n\nUnfortunately it turns out not to be that decent, and stop calling me Shirley. It\u2019s not exactly terrible code. It does recognise that a tag cloud is a list of links. And, since they\u2019re in alphabetical order, that it\u2019s an ordered list of links. That\u2019s nice. However \u2026 fifteen nested tags? FIFTEEN? That\u2019s emphasis for you. Yes, it is parse-able, but it\u2019s also something of a strange way of looking at emphasis. The HTML spec states that is emphasis, and is for stronger emphasis. Nesting tags seems counter to the idea that different tags are used for different levels of emphasis. Plus, if you had a screen reader that stressed the voice for emphasis, what would it do? Shout at you? Markup crime number three. \n\nSo what should it be? \n\nAs del.icio.us tells us, a tag cloud is a list of tags where the size that they are rendered at contains extra information. However, by hiding the extra context purely within the CSS or the HTML tags used, you are denying that context to some users. The basic assumption being made is that all users will be able to see the difference between font sizes, and this is demonstrably false. \n\nA better way to code a tag cloud is to put the context of the cloud within the content, not the markup or CSS alone. As an example, I\u2019m going to take some of my favourite flickr tags and put them into a cloud which communicates the relative frequency of each tag. \n\nTo start with a tag cloud in its most basic form is just a list of links. I am going to present them in alphabetical order, so I\u2019ll use an ordered list. Into each list item I add the number of photos I have with that particular tag. The tag itself is linked to the page on flickr which contains those photos. So we end up with this first example. To display this as a traditional tag cloud, we need to alter it in a few ways: \n\n\n\tThe items need to be displayed next to each other, rather than one-per-line\n\tThe context information should be hidden from display (but not from screen readers)\n\tThe tag should link to the page of items with that tag\n\n\nDisplaying the items next to each other simply means setting the display of the list elements to inline. The context can be hidden by wrapping it in a and then using the off-left method to hide it. And the link just means adding an anchor (with rel=\"tag\" for some extra microformats bonus points). So, now we have a simple collection of links in our second example. \n\nThe last stage is to add the sizes. Since we already have context in our content, the size is purely for visual rendering, so we can just use classes to define the different sizes. For my example, I\u2019ll use a range of class names from not-popular through ultra-popular, in order of smallest to largest, and then use CSS to define different font sizes. If you preferred, you could always use less verbose class names such as size1 through size6. Anyway, adding some classes and CSS gives us our final example, a semantic and more accessible tag cloud.", "year": "2006", "author": "Mark Norman Francis", "author_slug": "marknormanfrancis", "published": "2006-12-09T00:00:00+00:00", "url": "https://24ways.org/2006/marking-up-a-tag-cloud/", "topic": "code"}]