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RE: Caution about Style Sheets

From: Leonard R. Kasday <kasday@acm.org>
Date: Mon, 22 Jan 2001 09:39:24 -0500
Message-Id: <4.3.2.7.2.20010122092145.0254b760@pop3.concentric.net>
To: Charles McCathieNevile <charles@w3.org>, Robert Neff <rneff@bbnow.net>
Cc: <jim@jimthatcher.com>, "W3c-Wai-Ig@W3. Org" <w3c-wai-ig@w3.org>
To get back to the original question, what can go wrong when style sheets 
are turned off, one of the most dramatic is that reading worder can be 
broken.  A stylesheet can position headings and paragraphs in one way, and 
when you turn off style sheets the ordering is completely different, e.g. 
all the headings can be in a bunch the top or bottom.

It's easy for this to happen, and it has happened to us here.  All you have 
to do is use a page editing tool that allows you to drag things around on a 
page.  The author then writes some paragraphs and later positions the 
headings on top of the paragraphs.  The software uses CSS positioning to 
position the headings.  But they appear in the HTML in the order they were 
created and hence appear all in at the bottom (or at the top depending on 
how the software stacks things internally).

I don't know if this is what the 508 folks had in mind.  508 does not 
require that reading order be sensible when tables used for layout are 
linearized, so reading order may not be the reason for the CSS caution 
either.  But it's obviously a good reason nevertheless

Another thing that can go wrong is to use CSS classes that mean something, 
e.g. define a class that means "out of stock" which shows up in, say, 
italic or a particular font.  When you turn off style sheets there's no way 
to tell that an item is a member of that class, unless you have some 
redundant marking.

As for the consistency across views of a page seen by people working (or 
playing) together... that's an important point but I can't think of an 
obvious big impact of CSS on that issue in particular.  It comes more into 
play when you use things like XSL stylesheets or data driven sites which 
can more dramatically change how things look to different users.

Len


We've run into thisAt 11:02 PM 1/19/01 -0500, Charles McCathieNevile wrote:
>Actually breaking consistency can seriously break accessibility of a site in
>certain contexts. (That's why there is a checkpoint for consistency of
>navigation mechanisms for example). I belive Len Kasday is an expert on
>shared work environments, and the requiremnt that they impose for some kind
>of consistency - not absolute layout integrity in the print sense, but the
>functional equivalent in a user interface sense. So maybe he can comment on
>that.
>
>Thhere is also the qwuestion of priority. WCAG doesn't just specify things
>that are impossible or not impossible, unlike the approach apparently taken
>by the US 508. So things that are technically possible but painfully
>difficult, and effective blocks to reasonable efficiency (which is a major
>problem in a work environment) are listed in WCAG as Priority 2 requirements.
>
>Charles McCN
>
>On Wed, 17 Jan 2001, Robert Neff wrote:
>
>   Also think about what is readable here.  To me this means as long as the
>   words and meaning make sense.  Gow about an entire web site, does this need
>   to be degradable consistently or the same way across the entire web site?
>   Would be great for consistency, however, I do not think it would be
>   required.
>
>    -----Original Message-----
>   From:         w3c-wai-ig-request@w3.org 
> [mailto:w3c-wai-ig-request@w3.org]  On
>   Behalf Of Jim Thatcher
>   Sent: Tuesday, January 16, 2001 9:06 PM
>   To:   W3c-Wai-Ig@W3. Org
>   Subject:      Caution about Style Sheets
>
>   As you all know, the Section 508 standards include a slightly reworded
>   WCAG Checkpoint 6.1.
>
>   1194.22 (d) Documents shall be organized so they are readable without
>   requiring an associated style sheet.
>
>   What can go wrong with the use of style sheets that require this provision?
>   Thanks.
>
>   Jim
>   jim@jimthatcher.com
>   Accessibility Consulting
>   http://jimthatcher.com
>   512-306-0931
>
>
>
>--
>Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
>W3C Web Accessibility Initiative                      http://www.w3.org/WAI
>Location: I-cubed, 110 Victoria Street, Carlton VIC 3053, Australia
>until 6 January 2001 at:
>W3C INRIA, 2004 Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex, 
>France

--
Leonard R. Kasday, Ph.D.
Institute on Disabilities/UAP and Dept. of Electrical Engineering at Temple 
University
(215) 204-2247 (voice)                 (800) 750-7428 (TTY)
http://astro.temple.edu/~kasday         mailto:kasday@acm.org

Chair, W3C Web Accessibility Initiative Evaluation and Repair Tools Group
http://www.w3.org/WAI/ER/IG/

The WAVE web page accessibility evaluation assistant: 
http://www.temple.edu/inst_disabilities/piat/wave/
Received on Monday, 22 January 2001 09:39:47 GMT

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