HTML5 Shaping Up

HTML 5It's been a while since I last wrote about the upcoming HTML5 standard -two years to be precise- and a lot has happened since then. Not only has the W3C (World Wide Web Consortium ) draft moved closer to the finishing line, but quite a bit of the HTML5 package is already implemented and ready for deployment in modern browsers. Regarding the completeness of HTML5 support, Google Chrome is currently leading the pack, followed closely by Firefox, Opera and Safari. Even Microsoft seems to have discovered the advantage of standards compliance, as its upcoming IE9 includes support for several new HTML5 features. If you are a web developer and haven't delved into the details of HTML5 yet, now is the time.

As many web developers spend more time coding server side languages than coding HTML, they might think about HTML programming as a secondary skill. However, this contains the misconception that the new HTML5 standard is just about angle bracket tags. – It is not . – HTML is the heart wood of web programming and the upcoming HTML5 standard is the most comprehensive update that web developers have seen since the days of Mosaic. In this article, I am going to summarise some important points about HTML5 that every web developer should understand before moving on to the technical details.

HTML5 is not just about markup. Although the new HTML5 standard contains new tag definitions and deprecates old ones, the package goes far beyond markup definition. It does not just define new tags with new functionality, but it also defines the accompanying APIs in unprecedented detail. It contains diverse features for audio and video playback, 3D imaging, drag-and-drop, new form elements, a canvas element for 2D drawing, offline database storage, document editing, geolocation, microdata for semantic markup embedding, and CSS3, the next level of the cascading style sheets standard.

HTML5 is not going to be released with a drum-roll. The HTML5 specifications have been developed by the Web Hypertext Application Technology Working Group (WHATWG) of the W3C since 2004. The first public working draft was published in 2008. The specifications are considered an ongoing work and are expected to reach candidate recommendation stage within the next two years. In the meantime, the parts of the specification which are considered stable are being implemented by browser developers. Thus HTML5 is expected to reach the market in gradual steps over a number of years.

HTML5 is not all-or-nothing. Indeed, there was never an all-or-nothing scenario, even with prior versions of the HTML standard. Browser detection software typically doesn't test for HTML version support, but for individual features, such as support for a certain DOM level, API constructs, or specific feature implementations. Because HTML5 is a bundle of (largely independent) features and APIs, it will be no different with HTML5. For example, geolocation does not rely in any way on 3D imaging, the canvas does nor rely on drag-and-drop, and so on. Application developers can make use of these features without having to worry about HTML5 support on a whole.

HTML5 is designed with backwards compatibility. Upgrading your web pages to HTML5 might be as easy as replacing the HTML4 doctype tag with the HTML5 doctype. Chances are that all tags in a typical page -if they weren't already deprecated in HTML4- will still work in HTML5. Furthermore, the new standard enhances rather than replaces existing functionality. For example, the <input> tags in an HTML5 form may use the new input types for email, date, and numeric data entry. On older browsers without support for HTML5 tags, these are rendered as regular text input fields. The HTML5 form validation functionality, designed to simplify routine Javascript data validation, is also designed to be degradable in older browsers.

HTML5 is already here. Since the market introduction of HTML5 occurs incrementally,  many features are already available in up-to-date web browsers. For instance, semantic markup, canvas, and basic audio and video playback are already supported by the latest browser versions. One can safely assume that the upcoming Firefox 4 and IE 9 releases will put even more HTML5 features at the developer's disposal. Go to http://html5test.com to check your browser and find out which new features it already supports. See http://www.html5rocks.com for an interactive presentation, as well as in-depth tutorials and code examples of the new HTML5 features. Finally, a list of websites that already makes use of HTML5 (and ideas what it may be used for) can be found at http://html5gallery.com.