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xhtml media types

From: Beton, Richard <richard.beton@roke.co.uk>
Date: Tue, 15 Jun 2004 16:54:45 +0100
To: www-validator@w3.org
Message-ID: <40CF1BC5.2020407@roke.co.uk>

Nick Kew wrote:

>But you really shouldn't use XHTML 1.1 on the Web.  The 'majority' browser
>doesn't support it at all, unless you (illegally) serve it as broken HTML.
>  
>

Strictly, it's not illegal to serve XHTML 1.1 as "tag soup" text/html, 
but the specs say you SHOULD use application/xhtml+xml.

http://www.w3.org/TR/xhtml-media-types/ summary:
'application/xhtml+xml' **SHOULD** be used for XHTML Family documents, 
and the use of 'text/html' **SHOULD** be limited to HTML-compatible 
XHTML 1.0 documents.
'application/xml' and 'text/xml' **MAY** also be used, but whenever 
appropriate, 'application/xhtml+xml' **SHOULD** be used rather than 
those generic XML media types.

It does NOT say
the use of 'text/html' *MUST* be limited to HTML-compatible XHTML 1.0 
documents

The summary table is really clear: 
http://www.w3.org/TR/xhtml-media-types/#summary

In particular, note that XHTML1.1 is modularised and therefore 
extensible, but these extensions will fail unless it is served using the 
preferred application/xhtml+xml. But that does not mean that unextended 
XHTML1.1 will fail.  Indeed, being a proper subset of XHTML1.0 Strict, 
XHTML1.1 actually works pretty well on old browsers served as text/html 
in my experience.

Why use XHTML1.1? Because it's a proper subset with no <font> etc, so it 
forces you to use stylesheets properly.

Hope that clarifies things.  However, it raises a question in my mind: 
why does the spec not take a firmer stance on XHTML+MathML (the last 
column in the summary table cited above)? Old browsers won't render 
MathML, yet the spec says you *SHOULD NOT* (instead of *MUST NOT*) use 
text/html.

Rick :-)

[Note the precise use of the terms 'SHOULD', 'MAY' etc - 
http://www.rfc-editor.org/rfc/rfc2119.txt]

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Received on Tuesday, 15 June 2004 11:55:52 GMT

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