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Re: Minor error in CSS2, section 14.2; 'background'

From: L. David Baron <dbaron@fas.harvard.edu>
Date: Mon, 6 Sep 1999 22:30:46 -0400 (EDT)
Message-Id: <199909070230.WAA06092@ice2.fas.harvard.edu>
To: davidp@earthlink.net, www-style@w3.org
On Mon, 6 Sep 1999 14:30:29 -0700, "David Perrell"
(davidp@earthlink.net) wrote:

> I submit that the following revision of paragraphs three and
> four of [2] would be unequivocal and more in line with CSS
> cascading rules:

[snip]
> display properties. User agents should observe the following
> precedence rules to apply background-color and
> background-image to the canvas: If any property is declared
> for the HTML element, extend the HTML background onto the
> canvas, otherwise extend the BODY background onto the canvas.
> If the resulting background-color is 'transparent' or
> 'inherited' then the background-color of the canvas is
> undefined.

I think that's actually fundamentally against CSS cascading rules,
because it should not matter whether a property has its value (be it
'inherit' or not) because that value was declared or because the
property was given its default value.  So far, nothing in CSS has
broken this (to my knowledge) [1], although the temptation is sometimes
great to propose such rules.  The rule should depend only on what the
values are, not how they came to be.  Requiring knowledge of the source
of values would, I think, impose considerable difficulty on CSS
implementations.

David

[1] For some properties (those that inherit by default), the default
value is different for the root element, though.  A more logical way of
handling this might be to describe a super-root element where all the
properties' values are UA-dependant.  This might also explain:

HTML { font-size: 2em; }

which I believe is currently formally undefined.
Received on Monday, 6 September 1999 22:30:48 GMT

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