Re: HTML5 + xmlns validation issue

David Dorward, Fri, 9 Sep 2011 14:06:12 +0100:
> 
> On 8 Sep 2011, at 17:44, Silvia Malatini wrote:
> 
>> What is wrong with this? Is HTML5 not supporting namespaces? Or is 
>> the validator still incomplete? Or are we making any mistake?
> 
> From the specification "The HTML syntax does not support namespace 
> declarations, even in foreign elements."
> 
> http://www.w3.org/TR/html5/syntax.html#syntax

That's not the complete picture. The same document, HTML5, also permits 
xmlns="http://www.w3.org/1999/xhtml" in HTML. Not because it has any 
effect in HTML served as text/html, but in order to permit syntactic 
compatibility with XML parsers and XML producers.

The problem is thus also that the W3C's HTML5 validation service is 
incomplete/scewed: It supports HTML5+Microdata syntax, but stamps it as 
pure HTML5. [1] On the other side, it does not support HTML5+RDFa. If 
it did support HTML5+RDFa, then it would have been possible to declare 
the facebook prefix without being stamped as non-conforming. [2]

[1] http://www.w3.org/Bugs/Public/show_bug.cgi?id=14020
[2] http://www.w3.org/Bugs/Public/show_bug.cgi?id=14097
-- 
Leif Halvard Silli