W3C home > Mailing lists > Public > www-validator-css@w3.org > September 2005

Re: DIFFICULT VALIDATION

From: Jukka K. Korpela <jkorpela@cs.tut.fi>
Date: Sun, 18 Sep 2005 08:42:19 +0300 (EEST)
To: "john.angela@flyslikeabird.com" <john.angela@flyslikeabird.com>
Cc: www-validator-css@w3.org
Message-ID: <Pine.GSO.4.63.0509180830500.5337@korppi.cs.tut.fi>

On Sat, 17 Sep 2005, john.angela@flyslikeabird.com wrote:

> The validator demands a background colour

No, it issues a warning based on accessibility recommendations.

> so I set it as transparent.

Are you sure it is best to let the background color of the enclosing 
element shine through? No matter what that color is? (It might be set in a 
browser style sheet, or user style sheet.)

> A colour would run across graphics.

Indeed.

> Yet the validator still
> demands a background colour.

No, it does not. There's probably something wrong in the message's 
formulation if you a) interpreted it as an error message and
b) did not understand the point in its recommendation.

The misleading use of the word "validator" in the name of the program 
probably explains a) in part.

The main reason for b) is that this is a very difficult topic. Your 
understanding of CSS, especially inheritance and cascade, is well measured 
by your understanding of this issue, and I'm afraid most authors who use 
CSS never get the idea.

The background color is relevant even to elements that contain nothing but 
images and even to elements that have a background image. Consider what 
happens on a browser that will not display some or all of images, for one 
reason or another.

As regards to why transparent might not be good value, consider, for 
example, the following user style sheet
   * { background: black; color: white; }
when the author's style sheet sets just a background color (say, white or 
something light) for the body element and uses black as the text color.

-- 
Jukka "Yucca" Korpela, http://www.cs.tut.fi/~jkorpela/
Received on Sunday, 18 September 2005 05:42:26 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 27 June 2012 00:14:16 GMT