W3C officially opens HTML5 to scrutiny

The World Wide Web Consortium has reached an important point in the long journey to standardize HTML5, the next version of the Hypertext Markup Language used to describe Web pages.

HTML5 officially reached "last call" status last week, which means the W3C believes it's got a version of the specification mature enough for organizations to decide whether to express support. But changes still could come: "In practice, last call announcements generate comments that sometimes result in substantive changes to a document," the W3C said in announcing that HTML5 reached last call.

Hypertext Markup Language is a key plank of the World Wide Web technology created by Tim Berners-Lee, who remains involved as the W3C director. "We now invite new voices to let us know whether these specifications address a broad set of needs," he said in a statement.

But HTML5 also is a sore point for the group. HTML has steadily gained in importance as the Web grew far beyond its early roots. But the W3C largely abandoned HTML after releasing version 4.0.1 in 1999.

The W3C focused instead on an incompatible technology called XHML 2.0. That project didn't catch on among Web developers and browser makers, though; the latter formed their own group called the Web Hypertext Applications Technology Working Group (WHATWG) to advance HTML outside the W3C.

The W3C's work formed the foundation of HTML5 and some other related HTML specifications, and the W3C ultimately rejoined the effort. There's still a philosophical tension between the W3C and WHATWG, though: the W3C is working methodically to standardize HTML5 in 2014, but the WHATWG has abandoned HTML version numbers altogether in a shift to a more fluid, constant development process. The projects are still closely linked, though; the same person, a Google employee named Ian Hickson, is editor of both specifications.

HTML5 itself brings a number of changes.

One high-profile feature is an attempt to promote video and audio to the first-class status graphics enjoy rather than relying on plug-ins such as Adobe Systems' Flash Player. HTML5 video is conflicted, though, when it comes to the encoding technology used to actually stream video over the Web: browser makers Mozilla, Opera, and Google are fans of a Google project called WebM, which Google has released as royalty free and open source software. Apple and Microsoft, however, prefer the more mature and accepted but patent-encumbered H.264 encoding technology.

Another major feature of HTML5 is Canvas, a receptacle for a range of 2D graphics that can handle everything from computer-generated bar charts to an online game playing field.

HTML5 also tackles some thorny issues at the heart of browser makers' lives: how to digest, or parse, Web page code. HTML5's parser technology is based on a very broad examination of how HTML is used in practice on the Web, and the effort is intended to ensure that Web pages will look the same with different browsers. Accompanying the effort is a consistent way of handling errors in Web page coding, so those pages look the same, too.

The new standard also gets a range of new tags to label sections of a document more descriptively: section, header, and article, for example. That effort grew out of the recognition that many programmers had to resort to more laborious procedures to handle the same document structures over and over.

HTML5 promotes another piece of plumbing, the DOM (Document Object Model), to an official status. Ordinary people shouldn't have to care about the DOM, but they will care about what it's involved with--JavaScript programs that use the DOM to interact with Web page elements, for example. That's key to the much more sophisticated, dynamic Web pages often called Web apps.

HTML5 isn't the only HTML standardization work under way. Other HTML standards include geolocation, offline data storage, background processing, and a direct browser-server communication conduit called WebSockets.

On top of that, HTML5 often refers to a much broader collection of new Web features--WebGL for 3D graphics, Cascading Style Sheets for formatting and now animation, and fast JavaScript for more advanced Web app programming, for example. The W3C, while enthusiastic about much of that new work, generally sticks to the strict, narrow definition of HTML5.

For a look at what comes next in standardization, the W3C has released a schedule of upcoming steps in handling feedback, bugs that are filed, and moving on to the next stage.

For example, the W3C hopes to address all HTML5 objections by January 31, 2012.

In addition, with HTML5 reaching last call status, the W3C now plans to turn more attention to future features it calls HTML.next.

A final, important point: although the HTML5 standardization process is very drawn out, it's not charting some future ideas. More often, it's codifying the present, settling down practices already supported in browsers and used on the Web. So in many regards, HTML5 is already here.