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Suggested clarification on style sheets for wcag

From: Ian Jacobs <ij@w3.org>
Date: Tue, 15 Jun 1999 09:18:22 -0400
Message-ID: <3766529E.1DE31F3@w3.org>
To: w3c-wai-gl@w3.org

I think the WG should strengthen a statement
in the guidelines that any important 
content inserted by a style sheet be available in the 
document source as well (rationale: device-independence,
users can override styles, etc.)

The line between content and style is blurred by some
parts of CSS. Style sheets may cause numbers or words
to be generated in the rendering structure, just as they 
can insert images. Most users will have a difficult time 
distinguishing the document tree from the rendering structure, 
and will have to read the style sheets to find
out whether "1.2" was generated by styles (and therefore
may be changed through styles) or inserted by hand. 

In the Techniques document of 5 May, we raise this issue

   Text generated by style sheets is not part of the 
   document source and will not be available to assistive 
   technologies that access content through DOM, level 1 

I think we need to make a stronger point.

Here's an example. W3C Recommendations use a background image 
in the upper left hand corner to indicate on graphical browsers that
that they are Recommendations. There is no alt text for this
image since it's inserted by a style sheet (and CSS
has no
mechanism  for specifying alt text. On the one hand,
one can argue that if the information is being inserted
by a style sheet it is only meant for style, not content,
and therefore not alt text is necessary. On the other
hand, people argue that one shouldn't put text in images
but should use styles so that the text is accessible.
Also, languages like SVG that create graphics will real
text in them tout the accessibility benefits.

Does the title of the document suffice to convey
the document status?

 - Ian

Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel/Fax:                     +1 212 684-1814
Received on Tuesday, 15 June 1999 09:18:18 UTC

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