W3C Pulls Plug on XHTML 2
- By Joab Jackson
The World Wide Web Consortium (W3C) has halted work on the second version of the Extensible Hypertext Markup Language (XHTML), and has instead redirected its energies to the next version, HTML 5.
"When the XHTML 2 Working Group charter expires as scheduled at the end of 2009, the charter will not be renewed. By doing so, and by increasing resources in the HTML Working Group, W3C hopes to accelerate the progress of HTML 5," states a W3C news bulletin.
While early reports characterized the W3C's move as the death of XHTML, it is only an experimental version of the markup language that has gotten the axe. Most users of the language should not be affected, according to W3C's Mike Jones, who leads the HTML 5 working group.
"There is a big difference between XHTML 2 and XHTML," he said.
XHTML is a version of HTML that is rendered as a subset of Extensible Markup Language (XML) application. Casting HTML pages into an XML format allows their contents to be parsed more thoroughly by computers, though using XHTML involves more work on the part of Web site developers because XML documents need to be structurally coherent in a way that few HTML pages are.
Version 2 of XHTML is actually a complete rewrite of the markup language, Jones said. "Basically, the vision of XHTML 2 was to start over and fix all the mistakes with earlier versions of HTML," he said. "They were successful in [technical terms], but it never got market uptake. It never got native support in browsers."
Because version 2 was not backward compatible with version 1, which is widely used, few upgraded. XHTML 1, in contrast, is compatible with the current version of HTML, version 4.
Current users of XHTML 1 should not have to make any changes, Jones said. The next version of HTML now being developed, HTML 5, will be completely backward compatible with XHTML 1.
"What I tell people is make no changes at all to your current workflow. We will forever continue to support XHTML 1.0 as long as we're controlling the specification of HTML," Jones said. (Since HTML 5 has not been codified yet, it should not be used in production systems, he said).
New versions of XHTML may not be forthcoming, however.
"XHTML is just the name for one of the two syntaxes that are usable within browsers. All major browsers have two parsers — an XML parser and an HTML parser that can deal with non-well-formed content," Jones said. "We're not adding any specific new features to XHTML. We'll add new features to the abstract language that underlies both of those syntaxes."
One project that may be affected by the cancellation of XHTML 2 is a version of the Resource Description Framework called RDFa (the "a" standing for attributes). Search-engine services, such as Google, deploy RDFa. The impact to RDFa should be minimal, Jones said, because RDFa is already supported by XML.
"If you are working in XHTML and if you're documents are well formed, you can use RDFa and everything should work as designed," he said.
Joab Jackson is the chief technology editor of Government Computing News (GCN.com).