W3C home > Mailing lists > Public > www-talk@w3.org > May to June 2001

Re: text/html for xml extensions of XHTML

From: Ian Hickson <ian@hixie.ch>
Date: Fri, 4 May 2001 05:20:24 -0700 (Pacific Daylight Time)
To: "William F. Hammond" <hammond@csc.albany.edu>
cc: <mozilla-mathml@mozilla.org>, <www-talk@w3.org>
Message-ID: <Pine.WNT.4.31.0105040507550.988-100000@HIXIE.netscape.com>
On Fri, 4 May 2001, William F. Hammond wrote:
>
> Ian Hixie writes again in reply to Robert Miner:
>
>>> What I would like to be able to do is prepare an XHTML document in
>>> accordance with the HTML compatibility guidelines from Appendix C of
>>> the XHTML spec, *except* for the inclusion of MathML instances.
>>
>> In my opinion, browsers should not be promoting non-standard usage of W3C
>> technologies as you have just described.
>
> Ummm...  MathML instances, as namespace extensions of XHTML, are
> not in the problem category for classical user agents described by
> Appendix C.  Although the handling of these things with classical
> agents is not likely to be robust and content providers must be fully
> aware of that, it is misleading to say that namespace extensions for
> XHTML are outside of the territory where the Recommendation says that
> text/html may be used by a content provider.

As I said in [1], in my opinion there is very little point in sending
MathML to classical user agents. If you want to support older UAs, then
use <sup>, <sub> and tables for the equations. Otherwise you will have
dataloss -- your users won't be able to tell what you equations are doing.

Similarly, as I said in [2], if you wish to use MathML and still have
content available to your users on older user agents, make your index
pages HTML, and inform your readers that they will need more recent
browsers on those pages, then link to your text/xml pages with the text
and maths in them.

This is just like the many sites that have PDF documents on them but use
text/html index pages to link to them, with the index pages informing them
that they will need a plugin to view the documents.


[1] http://lists.w3.org/Archives/Public/www-talk/2001MayJun/0030.html
[2] http://lists.w3.org/Archives/Public/www-talk/2001MayJun/0043.html



> Namespace extensions are NOT on the list of 13 warnings to content
> providers in Appendix C.

Namespace extensions are invalid in XHTML 1.0 documents, so saying that
they shouldn't be included for compatability reasons would be somewhat
redundant. However, the section is entitiled "Compatibility Issues", and
thus the presence of MathML content in _well formed_ XHTML documents sent
as text/html (as opposed to valid XHTML documents sent as text/html) is,
in my opinion, against the spirit of the specification.


BTW, I just noticed C.11.13.5 says:

#    [...] HTML rules apply to XHTML documents delivered as HTML and the
#    XML rules apply to XHTML documents delivered as XML.

Now, this section is referring specifically to CSS' HTML rules vs CSS' XML
rules, but it gives an interesting insight into the working group's
intent, especially for those of you who don't accept my word that the HTML
working group have explicitly told Mozilla not to sniff for XML in
text/html data streams.

-- 
Ian Hickson                                            )\     _. - ._.)   fL
Invited Expert, CSS Working Group                     /. `- '  (  `--'
The views expressed in this message are strictly      `- , ) -  > ) \
personal and not those of Netscape or Mozilla. ________ (.' \) (.' -' ______
Received on Friday, 4 May 2001 08:17:38 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 27 October 2010 18:14:26 GMT