CSS 2.1 WD and non-CSS presentational hints

In this section:
     http://www.w3.org/TR/2002/WD-CSS21-20020802/changes.html#q74
the "CSS 2.1 Specification" working draft states:

|| If presentational hints from other sources than CSS are taken
|| into account by a UA, it must treat them as having the same weight
|| as the user agent's default style sheet. 

which is essentially the same as "CSS3 module: Cascading and inheritance"
<http://www.w3.org/TR/2002/WD-css3-cascade-20020219/#computing>:

||  If the user agent chooses to honor presentational hints from other
||  sources than style sheets, these hints must be given the same weight
||  as the user agent's default style sheet. This rule is intended for
||  presentational hints in HTML.  Note that non-CSS presentational hints
||  had a higher weight in CSS2. 


I cannot grasp the logic of this.  It seems to me to be a great mistake.


One of the more important functions of a user style sheet may be to
override choices in the user agent default style sheet.  By using "normal"
(that is, not !important) rules, the user can choose new defaults for
presentational attributes --- many of which may not be accessible for
modification in the user agent default style sheet.

This change would make it impossible to set defaults in a user style sheet
that could be overridden by old-fashioned HTML.  For example, in CSS2,
a user can include this rule in a user style sheet:
     BODY {color: navy; background: #FEC}
to make text appear, by default, in navy on a manilla background; a page
that specified either:
     BODY {color: white; background: url(dark.png) black}
or:
     <BODY TEXT=WHITE BGCOLOR=BLACK BACKGROUND="dark.png">
would override this and be displayed with the indicated attributes.  The
suggested change would have the thoroughly unintuitive and illogical result
of making these two display differently: the first would follow the author
specifications, but the second would follow the user specifications.


To a user, it makes no logical difference whether a particular effect comes
from a style sheet or an HTML presentational hint; these should not be
given opposite priorities with respect to the user style sheet.

This change might also present difficulties for user agents which could
otherwise implement user-selected presentational defaults as a (real or
virtual) user style sheet; it would instead be necessary to modify the
(real or virtual) user agent default style sheet to set these defaults.


Finally, I note that Internet Explorer 5 and 6 for Windows correctly
implement the *current* CSS2 specification:
     http://www.w3.org/TR/REC-CSS2/cascade.html#q12
in this regard.  This would seem to me to call into question the wisdom of
modifying it in CSS 2.1, even if there is reason to change it in CSS 3.

-- 
Randall Joseph Fellmy aka Randy@Coises.com

Received on Monday, 5 August 2002 09:09:14 UTC