Is this legal XHTML 1.1?

I've been playing around with XHTML 1.1 on Cafe con Leche today, 
mostly to see if I could get it to work. I made the usual changes 
from font tags and presentational attributes to CSS. I fixed a few 
malformedness errors that had snuck in. And I added some elements in 
places where XHTML required them.

However, there were a few changes I just didn't feel comfortable 
making for reasons of backwards compatibility. For instance, I wanted 
to keep a language attribute on my script element and a width 
attribute on my td element. And I had a couple of custom elements I 
didn't feel like giving up, so I wrote an internal DTD subset that 
made the necessary adjustments:

<!DOCTYPE
  html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
  "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd" [
  <!ENTITY % Block.extra "| today | quoteoftheday">
  <!ELEMENT quoteoftheday  (blockquote, p)>
  <!ELEMENT today ( h1 | h2 | h3 | h4 | h5 | h6 | ul | ol | dl | p | 
div | pre | blockquote | address | hr | table | form | fieldset | br 
| span | em | strong | dfn | code | samp | kbd | var | cite | abbr | 
acronym | q | tt | i | b | big | small | sub | sup | bdo | a | img | 
map | applet | ruby | input | select | textarea | label | button | 
ins | del | script | noscript)* >
  <!ATTLIST today
     date CDATA #REQUIRED
     id   ID    #REQUIRED >
<!ATTLIST script language NMTOKEN #IMPLIED>
<!ATTLIST td width NMTOKEN #IMPLIED>
]>

Is this legal? The W3C XHTML validator seems to think it is. It 
passes the document <http://www.cafeconleche.org/index.xhtml> without 
complaint. Adding custom elements like today and quoteoftheday to 
XHTML 1.1 is certainly blessed through profiling. But I'm using the 
backdoor instead. And using the internal DTD subset to sneak 
deprecated and obsolete attributes back into the language feels very 
suspicious.

Thoughts? Comments?
-- 

+-----------------------+------------------------+-------------------+
| Elliotte Rusty Harold | elharo@metalab.unc.edu | Writer/Programmer |
+-----------------------+------------------------+-------------------+
|          XML in a  Nutshell, 2nd Edition (O'Reilly, 2002)          |
|              http://www.cafeconleche.org/books/xian2/              |
|  http://www.amazon.com/exec/obidos/ISBN%3D0596002920/cafeaulaitA/  |
+----------------------------------+---------------------------------+
|  Read Cafe au Lait for Java News:  http://www.cafeaulait.org/      |
|  Read Cafe con Leche for XML News: http://www.cafeconleche.org/    |
+----------------------------------+---------------------------------+

Received on Sunday, 8 December 2002 13:55:06 UTC