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RE: Character encoding of linked HTML pages

From: Jo Rabin <jrabin@mtld.mobi>
Date: Fri, 18 Jan 2008 12:34:17 -0000
Message-ID: <C8FFD98530207F40BD8D2CAD608B50B4AD7698@mtldsvr01.DotMobi.local>
To: "Dominique Hazael-Massieux" <dom@w3.org>, "Herwig Feichtinger" <hf@isdn-capi.de>
Cc: <public-mobileok-checker@w3.org>

Hi Just to add to Dom's comment on this, you'll find the following statement in XHTML Media Types [1]:

"Note that a meta http-equiv statement will not be recognized by XML
processors, and authors SHOULD NOT include such a statement in an XHTML document served as 'application/xml' (and 'application/xhtml+xml' as well for that matter)."

Your reference on Character encodings [2] is consistent with this in that it says

"For HTML or XHTML served as HTML, you should always use the <meta> tag inside <head>."

The key point here is "served as html" under which circumstances [1] notes:

"... authors SHOULD include the XML declaration (e.g. <?xml version="1.0" encoding="EUC-JP"?>) and a meta http-equiv statement (e.g. <meta http-equiv="Content-Type" content="text/html; charset=EUC-JP" />).

[2] refers to some caveats on the use of the XML declaration [3].

In summary then, as Dom says the burden of doing the retrieval on link targets is great and the benefits limited because of the complexities noted here. The "warn" that is issued reflects the following advice from [1] in a number of places:

"... the use of an explicit charset parameter is STRONGLY RECOMMENDED" 

This reflects advice from RFC 3023 (XML media type, which is referred to from RFC 3236 - application/xhtml media type) and RFC 2854 (text/html media type).

Hope that helps
Jo


[1] http://www.w3.org/TR/2002/NOTE-xhtml-media-types-20020801/
[2] http://www.w3.org/International/O-charset
[3] http://www.w3.org/International/articles/serving-xhtml/#declaration



> -----Original Message-----
> From: public-mobileok-checker-request@w3.org [mailto:public-mobileok-
> checker-request@w3.org] On Behalf Of Dominique Hazael-Massieux
> Sent: 18 January 2008 11:08
> To: Herwig Feichtinger
> Cc: public-mobileok-checker@w3.org
> Subject: Re: Character encoding of linked HTML pages
> 
> 
> Hi Herwig,
> 
> Le vendredi 18 janvier 2008 à 11:43 +0100, Herwig Feichtinger a écrit :
> > It seems that the checker only looks for an encoding
> > in the HTTP header but not in the head area of
> > the HTML page,
> 
> Indeed; it would be too costly to download and parse   all the linked
> resources to make such an analysis.
> 
> The warning is meant to convey something that may be worth looking at,
> but is not necessarily broken.
> 
> Regards
> 
> Dom
> 
> 
Received on Friday, 18 January 2008 12:34:36 GMT

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