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AW: Type Attribute (was: AW: AW: XHTML 2.0 and hreflang and type)

From: Oskar Welzl <oskar.welzl@pan.at>
Date: Mon, 17 Nov 2003 21:43:28 +0100
To: "W3C HTML List" <www-html@w3.org>
Cc: "Lachlan Hunt" <lhunt07@postoffice.csu.edu.au>
Message-ID: <000201c3ad4b$749ffba0$0100a8c0@mshome.net>
> >you see, the main difference between a descripive HTML 4-@type 
> and the advisory/prescriptive @type in the XHTML 2.0 draft shows 
> when you consider 
> >
> ><span src="img.gif" type="image/png">hey?! what is it now??</span>
> >
> >let us assume the image is image/gif, not image/png. the author 
> simply made a mistake.
> >
>   I think this is the author's problem, not a problem with XHTML.  
> Author's need to take more care any way when writing XHTML 2.0, since 
> it's rules (particularly structure rules) are more strict than HTML 
> was.  We definatley want to stay as far away from those 
> tag-soup-browser's style of parsing, and rendering, of HTML as much as 
> possible.  So the above example should not be too much, if any, concern 
> for XHTML 2.0.

i couldn't agree more.
as you will notice when reading my original mail from which you cited, i used this example only to show that the suggested meaning of @type in XHTML 2 is much different from that in HTML 4. you might remember that you disagreed with my statement that @type in XHTML 2 was prescriptive. you said that both HTML 4 and XHTML 2 version are advisory only with XHTML 2 being even less restrictive, so from your point of view there was only a gradual difference. i wanted to show that there's more than that, that the concepts are extremely different.
the example was never intended to be used as a point against the current @type-proposal in XHTML 2.0

>   What's the point of the attribute, if the browser essentially ignores 
> it anyway, and just sends off it's request with it's default 
> accept header?

you'll see when you read the HTML 4.01 spec, 13.3 (OBJECT):
"...[@type]is optional but recommended when @data is specified since it allows the user agent to avoid loading information for unsupported content types. If the value of this attribute differs from the HTTP Content-Type returned by the server when the object is retrieved, the HTTP Content-Type takes precedence."
Nothing more to add here. 

> >...what about:
> ><p src="document" type="application/xhtml+xml, text/html">
> >what would the user agent do to guess which version of the 
> document is preferred... is it document.xml? document.html? 
> document.htm? ...
> >
>   How would a server make this decision, given the same situation?

a server might be configured to serve *.html as application/xhtml+xml and *.htm as text/html.


Received on Monday, 17 November 2003 15:42:13 UTC

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