Fwd: RE: Why Doesn't IE5 use the DTD to Validate?

Simon St.Laurent simonstl at simonstl.com
Thu Apr 1 05:47:07 BST 1999

This was on XSL.  I think its implications may be more interesting on this

Personally, I'm appalled, but I guess I shouldn't expect anything different.

>From: Jonathan Marsh <jmarsh at microsoft.com>
>To: "'xsl-list at mulberrytech.com'" <xsl-list at mulberrytech.com>
>Subject: RE: Why Doesn't  IE5 use the DTD to Validate?
>Date: Wed, 31 Mar 1999 14:02:31 -0800
>X-Mailer: Internet Mail Service (5.5.2524.0)
>Sender: owner-xsl-list at mulberrytech.com
>Reply-To: xsl-list at mulberrytech.com
>This is as designed, not a bug.
>The IE5 XML parser is a validating parser, with two properties set through
>DOM extensions to control DTD handling:
> - validateOnParse determines whether validation errors are presented to the
> - resolveExternals determines whether the DTD or XML Schema is loaded and
>datatypes, default values, etc. are honored.
>The values of these properties when browsing directly to XML documents is
>validateOnParse=false and resolveExternals=true.
>When browsing XML documents on the Web, surfacing validation errors is of
>little apparent value.  I would not expect publishers to author both a DTD
>or XML Schema and documents that don't conform to that DTD/Schema.  So the
>vast majority will not generate validation errors.  For those that declare a
>DTD and are invalid, is it no better to give the user a validation error
>instead of displaying the document, in fact the validation error could
>prevent the user from viewing an otherwise perfectly good document.  Also
>the performance penalty for validation is significant and should not be
>imposed on end-users without good reason.
>The only scenario we could come up with where validation is useful when
>browsing XML documents is when the browser is used as a development tool,
>allowing easy checking of well-formedness and validation for a document in
>progress.  This scenario can be accomplished by a number of alternative
>mechanisms without impacting the browsing experience - a simple tool that
>validates an XML document could be written in a few lines of JavaScript, see
>lt.asp for an example.
>We considered several mechanisms for allowing developers to "turn on"
>validation errors but did not find a clean solution that could be
>implemented in time for the IE5 release.
>- Jonathan Marsh
>> -----Original Message-----
>> From: Sall, Ken [mailto:ksall at cen.com]
>> Sent: Wednesday, March 31, 1999 6:37 AM
>> To: 'xsl-list at mulberrytech.com'
>> Subject: RE: Why Doesn't IE5 use the DTD to Validate?
>> Thanks, Stephen.
>> I've added an example that illustrates your point that IE5 detects DTD
>> syntax errors.
>> http://members.home.com/kensall/tests/collection1bugsdtd.xml
>> http://members.home.com/kensall/tests/collection1bugs.dtd
>> However, if anyone from Microsoft can explain why IE5 doesn't 
>> actually use
>> the DTD to validate the document (the way that IE5 Beta 2 did), I'd
>> appreciate it. This problem will be published in an article 
>> shortly (in the
>> larger context of positive things you can do with IE5 with 
>> XML/XSL) and it
>> would be great to state correctly what Microsoft plans w.r.t. DTD
>> processing. 
>> TIA
>> - Ken Sall                           ksall at cen.com, kensall at home.com
>> - Century Computing, Inc.            http://www.cen.com/
>> - NG-HTML: Next Generation HTML      http://www.cen.com/ng-html/
>> - XML at Web Developers Virtual Lib
>> http://WDVL.com/Authoring/Languages/XML/
>> - MW3: Motif on the World Wide Web   http://www.cen.com/mw3/
>> > -----Original Message-----
>> > From: Stephen Ransom [mailto:sransom at objectmastery.com]
>> > Sent: Wednesday, March 31, 1999 1:52 AM
>> > To: xsl-list at mulberrytech.com
>> > Subject: Re: Why Doesn't IE5 use the DTD to Validate?
>> > 
>> > 
>> > > It doesn't appear that IE5 (March 18th release) uses the 
>> > DTD to validate
>> > > XML, as did the IE5 Beta 2 release. Has anyone been able to 
>> > make IE5 detect
>> > > when a doc doesn't follow the rules of the DTD that it references?
>> > 
>> > I agree that IE5 appears to "lose" the errors in a well 
>> > formed but invalid XML
>> > document (ie one written in proper XML but which fails to 
>> meet its DTD
>> > definition).
>> > 
>> > I note however that IE5 is aware of the DTD even though it 
>> > will pass through a
>> > failing XML document. This can be shown by adding a line of 
>> > XXXX's into the DTD
>> > itself (thus breaking the DTD's well-formedness). IE5 will 
>> > give you an error
>> > message identifying the XXXX's as incorrect.
>> > 
>> > Stephen
>> > 
>> > 
>> > 
>> >  XSL-List info and archive:  
>> http://www.mulberrytech.com/xsl/xsl-list
>> > 
>>  XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list
> XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list
Simon St.Laurent
XML: A Primer
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