Web Changes

On top of all the concerns that web developers have about using XML for serving documents, XHTML2 adds another layer of complexity. It isn’t HTML 4.01 reformulated as XML; it’s a different but similar language, with added, removed, or modified semantics for many elements, and added or changed element vocabulary for many semantics.

HTML 4.01 was made a recommendation in 1999, XHTML 1.0—a formulation of HTML 4.01 in XML—became a recommendation in 2000, and was revised in 2002. In other words, at the base of all modern web development is an eight-year-old technology.

The Contenders

The W3C has long had XHTML2 in the works, a technology that aims to fill the same role as HTML 4.01 and XHTML 1.0, an upgrade or replacement with many improvements and changes to the semantic elements available. XHTML2 is XML—just as XHTML 1.0 is—but it doesn’t have backward compatibility to HTML 4.01. It can, in fact, be considered an entirely new language, something made very clear by the fact it has a completely different namespace.

HTML5 (also sometimes referred to as Web Applications 1.0) is a technology developed by the WHATWG, an open community started by three of the four major browser vendors: Mozilla, Opera, and Apple. HTML5 is not so much a replacement for HTML 4.01 or XHTML 1.0 as it is an upgrade or evolution. It aims for backwards compatibility, tries to remove undefined behavior in HTML 4.01 by defining it, and looks at the various browsers’ tag-soup parsing behavior to try to define the best solution that doesn’t break the web. At the same time, it adds sorely needed semantic elements for things such as improved form validation, interactive elements, and persistent storage.