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XHTML - two questions

From: Stefan Mintert <mintert@irb.informatik.uni-dortmund.de>
Date: Thu, 25 Feb 1999 14:18:43 +0100
Message-Id: <199902251318.OAA09771@brown.informatik.uni-dortmund.de>
To: www-html@w3.org
cc: mintert@irb.informatik.uni-dortmund.de



Hi!


I have two questions concerning the XHTML 1.0 WD (WD-html-in-xml-19990224).
Thanks in advance for any answers.


====================
1.3 Why the need for XHTML?
[...]
Under SGML, the
     addition of a new group of elements would mean
     alteration of the entire DTD. In an XML-based
     DTD, all that is required is that the new set of
     elements be internally consistent and well-formed
     to be added to an existing DTD. 
====================


I don't understand this statement. 

1) Why do I need to alter the *entire* DTD under SGML? I have to modify the
content models of some old element types to allow some new element types as
child elements. 

2) If I add a new set of elements to a XML DTD by putting the appropriate
<!ELEMENT ..> declarations at the end of the DTD, what does that help? As
long as none of the new element types is included in the content model of
some of the old element types, this change has no affect. I have to alter the
old DTD. Where's the difference to SGML?




====================
4.1.6 Empty Elements
Empty elements must end with />. 
====================

What about <br></br> which is legal in XML 1.0: "If an element is empty, it
must be represented either by a start-tag immediately followed by an end-tag
or by an empty-element tag."
(http://www.w3.org/TR/1998/REC-xml-19980210#sec-starttags)

Is it not allowed to write <br></br> in XHTML? 



Bye,

  Stefan.

+-----------------------------------------------------------+
  Stefan Mintert        
       UniDo:    mintert@irb.informatik.uni-dortmund.de
       private:  stefan@mintert.com
+-----------------------------------------------------------+


        "let the music keep our spirits high..."

                                (Jackson Browne)
Received on Thursday, 25 February 1999 08:18:50 GMT

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