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Re: Failure and Technique for CSS Generated Content

From: Ben Caldwell <caldwell@trace.wisc.edu>
Date: Tue, 08 Apr 2008 17:40:15 -0500
Message-ID: <47FBF44F.8020505@trace.wisc.edu>
To: Cynthia Shelly <cyns@exchange.microsoft.com>
CC: WCAG <w3c-wai-gl@w3.org>

Thanks Cynthia,

Good catch. I agree that generated content is a important issue that 
and have drafted a failure to help get things started.

Failure of 1.3.1 due to inserting non-decorative content via CSS

I'm not sure that F3 should be listed as a failure of 1.3.1 since it 
would be possible for a page to include images that convey information 
via CSS as long as that information is also available to assistive 
technologies. (ex. the CSS could both position a parenthetical such as 
"(external link)" off screen and insert an icon that conveyed the same 

I believe that support for other types of generated content is largely 
an issue of whether or not they are supported by the user agent in use, 
but agree that we should explore the other questions you raised in 
greater detail.


Cynthia Shelly wrote:
> I think we need to address text content added via CSS, also called
> Generated Content.  By spec, this content does not get added to the
> DOM. So, it's not programmatically determinable.  I'd like to propose
> the following:
> Failure of 1.3.1 due to adding information in text with CSS
> CSS Technique:  Adding purely decorative text with CSS
> Changes to F3: F3: Failure of Success Criterion 1.1.1 <ins>and
> 1.3.1</ins> due to using CSS to include images that convey
> <del>important</del> information Add example:  using CSS to add an
> icon next to links that leave the current site
> We need to go through this spec [1] on CSS Generated Content, and
> decide what, exactly, should be allowed to be added through GC in a
> WCAG-compliant document, and put each example in either the failure
> or the technique.
> For example, when is it ok to the following in a way that's not
> programmatically determinable:
> * change list numbers * add quotation marks * add "Note:" before a
> element, or chapter before a header * add icons * change list bullets
> into icons * change list bullets into a different decorative item *
> add text using the content property, or the :before and :after
> pseudo-elements
> [1] http://www.w3.org/TR/CSS21/generate.html

Ben Caldwell | <caldwell@trace.wisc.edu>
Trace Research and Development Center <http://trace.wisc.edu>
Received on Tuesday, 8 April 2008 22:40:55 UTC

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