Re: RDFa and its relationship to XHTML

On Fri, 09 Jun 2006 01:56:24 +0200, Karl Dubost <karl@w3.org> wrote:

> I think there is often a misunderstanding about what is a validator.
> 	The validator doesn't reject anything,

I disagree here.

[snip]

> As for the XHTML 1.0 specification.
>
>     XHTML 1.0 *strictly* conforming document:
> 	*Valid* document according to the DTD.
>
> 	[[[
> 	It must conform to the constraints expressed in one of
> 	the three DTDs found in DTDs and in Appendix B.
> 	]]]
> 	-- XHTML 1.0: The Extensible HyperText Markup Language (Second Edition)
> 	http://www.w3.org/TR/xhtml1/#strict
> 	Thu, 01 Aug 2002 13:56:02 GMT
> 	
>     XHTML 1.0 with other namespaces:
> 	*Well-formed* document
> 	http://www.w3.org/TR/xhtml1/#well-formed
>
> 	[[[
> 	The XHTML namespace may be used with other XML
> 	namespaces as per [XMLNS], although such documents
> 	are not strictly conforming XHTML 1.0 documents as
> 	defined above. Work by W3C is addressing ways to
> 	specify conformance for documents involving multiple
> 	namespaces. For an example, see [XHTML+MathML].
> 	]]]
>
> 	-- XHTML 1.0: The Extensible HyperText Markup Language (Second Edition)
> 	http://www.w3.org/TR/xhtml1/#strict
> 	Thu, 01 Aug 2002 13:56:02 GMT
>
>
> So as I said,
> 	- namespaces are not valid BY design BY the specification.

No. Namespaces are not valid due to a lack of ability by DTDs to handle  
them.

The XHTML 1 spec also says:

"If a user agent encounters an attribute it does not recognize, it must  
ignore the entire attribute specification (i.e., the attribute and its  
value)."
http://www.w3.org/TR/xhtml1/#uaconf

Which covers things like xmlns attributes. The document may not then be  
'strictly valid', because DTDs are unable to define such rules, but you  
can call it conformant.

Best wishes,

Steven