W3C home > Mailing lists > Public > www-validator@w3.org > January 2001

Re: CSS and XHTML

From: Ian Jacobs <ij@w3.org>
Date: Thu, 11 Jan 2001 19:44:38 -0500
Message-ID: <3A5E5376.CC8750D0@w3.org>
To: pdf@bizfon.com
CC: www-validator@w3.org
pdf@bizfon.com wrote:
> 
> In the "XHTML 1.0: The Extensible HyperText Markup Language" document, located
> here:
> http://www.w3.org/TR/2000/REC-xhtml1-20000126/
> 
> Appendix C (C.13) states:
> CSS style sheets for XHTML should use lower case element and attribute names.
> 
> So then if my page contains this:
> <style type="text/css">
> BODY {}
> #TOPTITLE {}
> </style>
> 
> is that no good?  I'm not sure what the document 
> means by "element and attribute
> names" in a CSS document.  I can understand the 
> element requirement to be lower
> case (since html elements must be written in lowercase), 
> but I don't know when
> you would possibly specify an attribute name in a CSS 
> document.  For the record,
> my document validates with the above style.  
> Should this validate?

Here's my take:

1) "All CSS style sheets are case-insensitive, except for
    parts that are not under the control of CSS. For
    example, the case-sensitivity of values of the HTML 
    attributes "id" and "class", of font names, and of
    URIs lies outside the scope of this specification. 
    Note in particular that element names are
    case-insensitive in HTML, but case-sensitive in XML. "
     -- CSS2, section 4.1.3
       http://www.w3.org/TR/1998/REC-CSS2-19980512/syndata.html#q4

    This suggests to me that:

    * CSS doesn't care whether you write "body" or "BODY" 
      because that's "outside" CSS.

    * When CSS is used in the context of XHTML, then
      case does matter, so you shouldn't use "BODY", because
      that doesn't match "body". 

    * Strictly speaking, it's not the validator's job 
      to detect that you have used BODY and should have used
      body. All the validator cares about is that you've put
      CDATA in the style element.

    * Perhaps an extra feature of the validator would be to
      validate that element and attribute selectors in
      xhtml documents were lower case. But that would require
      special case programming (though I don't know since I
      didn't write the validator).

2) "CSS2 allows authors to specify rules that match 
   attributes defined in the source document."
    -- CSS2, section 5.8
 
http://www.w3.org/TR/1998/REC-CSS2-19980512/selector.html#attribute-selectors


- Ian

-- 
Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel:                         +1 831 457-2842
Cell:                        +1 917 450-8783
Received on Thursday, 11 January 2001 19:44:40 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 25 April 2012 12:13:55 GMT