[development] HTML5, XHTML2, and the Future of the Web

[Karoly Negyesi]

http://www.digital-web.com/articles/html5_xhtml2_and_the_future_of_the_web/

Quotes:

The fact that Internet Explorer doesn’t really support XHTML as XML in any  
way, and the problems XML can cause when not all tools in the authoring  
chain are XML tools, means that there has been little incentive for using  
XML on the web. This is compounded by search engines not indexing XHTML as  
XML documents; very few XHTML authoring tools for XML; very few CMS or  
blogging tools supporting XML correctly all the way from input through  
database to generation; and very few ad suppliers supporting XML.

While HTML 4.01 is formally SGML-based, HTML5 accepts the reality of all  
browsers using error-correcting tag-soup parsers, and instead describes a  
specific non-SGML parsing model that includes a defined error correction  
model.

Turning an HTML 4.01 document into HTML5, on the other hand, is in most  
cases just a question of replacing the DOCTYPE declaration. If a document  
doesn’t use any of the new elements or APIs introduced by HTML5, the  
browser just sends it to its tag-soup parser. For most current  
content-management systems and authoring tools, the change to generate  
HTML5 instead of HTML 4.01 is simple, and the new HTML5 features can be  
added to them easily. In addition, many of the new HTML5 features can be  
emulated using JavaScript for browsers that don’t support them, allowing  
for a gradual change from HTML 4.01 to HTML5.