XHTML2 has reached it’s fifth working draft, and the blurb from the W3C:
XHTML2.0 is a markup language intended for rich, portable web-based applications. While the ancestry of XHTML2.0 comes from HTML4, XHTML1.0, and XHTML1.1, it is not intended to be backward compatible with its earlier versions. Application developers familiar with earlier its ancestors will be comfortable working with XHTML2.0.
XHTML2 is a member of the XHTML Family of markup languages. It is an XHTML Host Language as defined in Modularization of XHTML. As such, it is made up of a set of XHTML Modules that together describe the elements and attributes of the language, and their content model. XHTML2.0 updates many of the modules defined in Modularization of XHTML, and includes the updated versions of all those modules and their semantics. XHTML2.0 also uses modules from Ruby, XML Events, and XForms.
Public discussion of XHTML takes place on www-html@w3.org (archive). To subscribe send an email to www-html-request@w3.org with the word subscribe in the subject line.
The W3C has gone back to it’s roots with regards to document structure for XHTML2 and therefore not meant to be backwards compatable, as outlined in Section 1.1.1 and Section 1.1.2:
Because earlier versions of HTML were special-purpose languages, it was necessary to ensure a level of backwards compatibility with new versions so that new documents would still be usable in older browsers. However, thanks to XML and stylesheets, such strict element-wise backwards compatibility is no longer necessary, since an XML-based browser, of which at the time of writing means more than 95% of browsers in use, can process new markup languages without having to be updated. Much of XHTML2 works already in existing browsers. Much, but not all: just as when forms and tables were added to HTML, and people had to wait for new version of browsers before being able to use the new facilities, some parts of XHTML2, such as XForms and XML Events, still require user agents that understand that functionality.
The original version of HTML was designed to represent the structure of a document, not its presentation. Even though presentation-oriented elements were later added to the language by browser manufacturers, HTML is at heart a document structuring language. XHTML2 takes HTML back to these roots, by removing all presentation elements, and subordinating all presentation to stylesheets. This gives greater flexibility, and more powerful presentation possibilities, since CSS can do more than the presentational elements of HTML ever did.
Basically, it’s possible to use XHTML2 now as it’s “just” XML, and using XSLT either server-side or client-side to display the data. Obviously this isn’t recommended as being a specification in progress, things change.
Though long, the specification does make for interesting reading. :D
