XHTML 1.1 DTD is broken, additional sub-dtd pages included from primary dtd missing from w3.org website, causes validation error


    I was experimenting with XHTML version 1.1. Yes, I know that it is 
superseded by XHTML5, but, there is no official DTD or XSD for XHTML5. I 
wanted to try testing validation of an XML document with a command line 
XML validator tool. I was then, once I knew it was working correctly, 
going to try getting an xhtml5 document and seeing if I could validate 
against the unofficial v.Nu xhtml5 relaxng schemas.

According to the page:


A valid xhtml11 document MUST include both a DOCTYPE referencing the DTD 
and MAY include a reference to the XSD. The following is the recommended 
DOCTYPE and root html element:

<html xmlns="http://www.w3.org/1999/xhtml"  xml:lang="en"
       xsi:schemaLocation="http://www.w3.org/1999/xhtml http://www.w3.org/MarkUp/SCHEMA/xhtml11.xsd"

When I attempted to validate my .xhtml document which included the 
above, since there was a DTD declaration, the validator automatically 
attempted to validate against the DTD at:


The validator threw the following error:


Since my document doesn't directly reference that URL, I figured that it 
must be included from xhtml11.dtd, and I verified that by going and 
searching in the file xhtml11.dtd, and yes, indeed it does include it.

So, I tried loading that URL in my browser, and got a 404 page not found 

So, this means that one cannot validate against the public xhtml11 dtd 
published on the w3.org website currently. I know this is a superseded 
standard, but, the validation files should still be available and should 
forever be available on the w3.org website, because even though it's 
superseded, people should still be able to use it if they so choose and 
it meets their needs, and additionally, they may need to validate and 
process legacy xhtml files generated either in the past, or by old web 
apps/sites that were written against xhtml11.

Please fix this missing page (and any other pages that may also be 
missing from the site) so that xhtml validation against the dtd works 
(although, ideally, I'd like my documents to validate against the xsd, 
not the dtd, but currently, I haven't found a way to get the java 
validator code to ignore the DOCTYPE and just validate against the DTD, 
except to remove the DOCTYPE element (which, then my doc DID validate 
successfully against the xsd).

Received on Monday, 9 January 2023 21:31:37 UTC