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Re: XHTML

From: Murray Altheim <altheim@eng.sun.com>
Date: Wed, 24 Nov 1999 14:23:04 -0800
Message-ID: <383C6548.665A66CB@eng.sun.com>
To: "L. David Baron" <dbaron@fas.harvard.edu>
CC: www-html@w3.org
"L. David Baron" wrote:
> 
> On Wed, 24 Nov 1999 13:20:51 -0800, Murray Altheim
> (altheim@eng.sun.com) wrote:
> >
> > The fact that it "works" (using your earlier idea of CSS1 being "fully
> > implemented") in IE doesn't mean that in an arbitrary XML document (ie.,
> > not HTML or XHTML) you can rely on it to work correctly (interpreting
> > the XML DOM correctly) in other applications. Microsoft may have an XML
> > support for CSS (like simply allowing any element type rather than
> > HTML's) that suits your needs, but that hardly means that CSS is not
> > proprietary to HTML. As the principle editor of the CSS1 Recommendation
> 
> You said it can't be relied on to work correctly.  But *why* do you
> think it won't work correctly?  What's the problem?

Go look at the HTML and XML DOMs. They are different. You can't design
a language that works the same, interoperably, in both DOMs. They will
provide different behaviour with the same syntax. Also, if you look at
the XPath WD [XPATH] you'll see many of the design decisions that were
necessary in XML to provide a functional selector syntax (XPath is used
both in XSL and XLink to provide the same type of node selection 
functionality). The CSS selector syntax was not designed for generic
language usage. 

For a simple example, HTML uses 'class' attributes, so CSS is designed
to key off of class attribute values. These attributes have no special 
significance in XML, and in fact an XML language designer might decide
to name an attribute 'class' and use it in an alternative way. They
might want to key off of an entirely different attribute value. There's
no way to do that in CSS. And what about the difference between "Class",
"class" and "CLASS" in XML? Case matters, but not in HTML/CSS. I really
could go on for about ten minutes on this, but perhaps you already see
my point: CSS was designed for HTML, not generic XML markup. CSS2 is an
attempt to alter CSS so that it might be suitable for XML. Since I've 
yet to hear of a working implementation (or plans to implement it widely)
of CSS2 in commercial browsers since even CSS1 has a ways to go [2], I'm
putting my energies into XSL, as are my colleagues at Sun.

Murray

[1] "XML Path Language (XPath) Version 1.0: W3C Recommendation",
    James Clark, Steve DeRose, 16 November 1999.
    http://www.w3.org/TR/xpath.html
[2] WebReview, which reports that #ID is broken in *all* implementations,
    whitespace, box and border properties in most. The level of unsupported
    CSS listed in this review is quite enlightening and completely belies
    statements that full CSS1 support is widespread.
    http://webreview.com/pub/guides/style/style.html
...........................................................................
Murray Altheim                                   <mailto:altheim@sonic.net>
Member of Technical Staff, Tools Development & Support
Sun Microsystems, Inc. MS MPK17-102
1601 Willow Rd., Menlo Park, California 94025  <mailto:altheim@eng.sun.com>

   the honey bee is sad and cross and wicked as a weasel
   and when she perches on you boss she leaves a little measle -- archy
Received on Thursday, 25 November 1999 00:28:50 GMT

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