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content type for XHTML fragments: reformulated

From: Garret Wilson <garret@globalmentor.com>
Date: Mon, 16 Jan 2006 13:52:33 -0800
Message-ID: <43CC15A1.5050708@globalmentor.com>
To: www-html@w3.org

There has been a bit of confusion about this question, so let restate 
succinctly the query.

Question: What content type should be used for XHTML fragments stored 
independently of any XHTML document?

Example: "this is <em xmlns="http://www.w3.org/1999/xhtml">really</em> cool"

Context: An application (e.g. a wiki or a newsfeed) might elect to store 
snippets of XHTML information in independent files, and later assemble 
these bits of comments into a single XHTML document to present to the 
browser. Obviously the application must be able to distinguish between 
plain text files and markup files---otherwise it would be ambiguous 
whether "this is <em xmlns="http://www.w3.org/1999/xhtml">really</em> 
cool" should be integrated into the XHTML document as a plain text 
string (and therefore '<' should be encoded as &lt;, for example), or 
whether the string should be interpreted as actually defining a 
hierarchy of XHTML elements.

Relevance to www-html: RFC 3236, "The 'application/xhtml+xml' Media 
Type" ( http://www.ietf.org/rfc/rfc3236.txt ), clearly states, "Please 
send comments to www-html@w3.org...." (section 1). This is not a "how 
to" question, but a "which one" question.

Related Text from RFC 3236:

    With respect to XHTML Modularization [XHTMLMOD] and the existence
    of XHTML based languages (referred to as XHTML family members)
    that are not XHTML 1.0 conformant languages, it is possible that
    'application/xhtml+xml' may be used to describe some of these
    documents. ...

    Although conformant 'application/xhtml+xml' interpreters can
    expect that content received is well-formed XML (as defined in
    [XML]), it cannot be guaranteed that the content is valid XHTML
    (as defined in [XHTML1]).  This is in large part due to the
    reasons in the preceding paragraph. (section 2)

Possible Responses:

* Use "application/xhtml+xml", because this content type can be applied 
to XHTML content that does not constitute a complete XHTML 
document---but wrap the fragment in an outer element such as "<span 
xmlns="http://www.w3.org/1999/xhtml">this is <em>really</em> cool</span>".

* Use "text/xml" or "application/xml" and wrap the fragment in an outer 
element.

* Use "application/xml-external-parsed-entity" and wrap the fragment in 
an outer element.

Is there no specification that defines the content type of an XHTML 
fragment? XHTML requires an <html> element for XHTML documents, but it 
seems to me that a "marked-up XHTML string that is not an XHTML 
document" is a very common use case. Therefore so it's necessary to 
determine what the standard content type would be for such an XHTML 
fragment.

Garret
Received on Monday, 16 January 2006 21:52:45 GMT

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