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Possible problem with Fahrner Image Replacement

From: Joe Clark <joeclark@joeclark.org>
Date: Mon, 14 Jul 2003 22:26:35 -0400
Message-Id: <a06001802bb3912495dab@[]>
To: WAI-IG <w3c-wai-ig@w3.org>, uvip-web-test@yahoogroups.com

Fahrner Image Replacement, named after Todd Fahrner (but apparently 
invented by C.Z. Robertson), is a standards-compliant technique that 
uses stylesheets to provide a visible image, usually of 
nicely-typeset words, that is backed up by marked-up plain text. All 
the hip kids are using it.


Back in March, I had people try FIR in Window-Eyes and Home Page 
Reader, and two of the test pages at 
<http://www.stopdesign.com/log/default.asp?date=20030314> read 
correctly. I suppose it is a problem that all three did not.

There is, however, the problem that screen readers are yoked to 
visual browsers and inherit their stylesheet interpretations. 
{display: none} really means {display: none}, and the treatment of 
visibility: hidden is unclear.

The result?

One correspondent, using HPR on his machine, says that text marked up 
as FIR disappears completely because it isn't an img element with 
alt; also, {display: none} takes it out of the reading order 

You can test this on my new, all-CSS page for Ten Years Ago in _Spy_, 
fixed up by Matt Mullenweg:


I need people to throw every screen reader they've got at that simple 
page <http://www.fawny.org/spy/?FIR> and see if you can read the text 
embedded in graphics. There are two separate blocks, and I'm not 
gonna tell you what they say-- the purpose is to see if you can read 

Use all screen readers you have, *especially Jaws*, though I doubt 
anyone from Freedom Scientific would bother looking into this.

Report back to me and I will summarize to the lists.

If this technique is really not working, then the most advanced 
standards-compliant sites designed by the most conscientious people 
at work today have a serious problem-- one of the problems they were 
going very much out of their way to avoid.


     Joe Clark | joeclark@joeclark.org
     Accessibility <http://joeclark.org/access/>
     Author, _Building Accessible Websites_
Received on Monday, 14 July 2003 22:25:42 UTC

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