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RE: Text for images used as links

From: John M Slatin <john_slatin@austin.utexas.edu>
Date: Sun, 29 May 2005 15:41:37 -0500
Message-ID: <6EED8F7006A883459D4818686BCE3B3B0153D169@MAIL01.austin.utexas.edu>
To: "Jon Hanna" <jon@hackcraft.net>, <w3c-wai-ig@w3.org>

Vicente Luque Centeno wrote:

> WCAG 2.0 says:
>     "When an image is used as the content of a link, specify a text
> alternative for the image. The text alternative should describe the 
> function of the link."

This is *not* a quotation from the current public working draft of WCAG 2.0 (19 November 2004) available at http://www.w3.org/tr/wcag20/! I also looked for these words in General Techniques for WCAG 2.0 L1 SC1   (at http://www.w3.org/TR/2004/WD-WCAG20-GENERAL-20041119/text-equiv-functional.html) and in HTML Techniques for WCAG 2.0 (at http://www.w3.org/TR/WCAG20-HTML-TECHS/#img-alt)  and didn't find a match.  What source are you quoting from?

In the current Public Working Draft of WCAG 2.0,  Guideline 1.1 reads as follows:

<q>Provide text alternatives for all non-text content.</q>

Under the heading Level 1 success criteria for Guideline 1.1 there are 6 success criteria that must be satisfied.  Each success criterion is a testable statement (one tht may be either true or false for a given bit of non-text content).

In this draft, the success criteria for Guideline 1.1, Level 1 are as follows:

<blockquote cite="http://www.w3.org/tr/wcag20/">
1. For all non-text content that is functional, such as  graphical links or buttons, text alternatives serve the same purpose as the non-text content.
2. For all non-text content that is used to convey information,  text alternatives convey information.
3. For non-text content that is intended to convey a specific sensory experience, such as music or visual art, text alternatives identify and describe the non-text content.
4. Non-text content that does not provide information, functionality, or sensory experience is marked such that it can be ignored by assistive technology.
5. Any text alternatives are explicitly associated with the non-text content.
6. For live audio-only or live video-only content, such as internet radio or Web cameras, text alternatives describe the purpose of the presentation or
a link is provided to alternative real-time content, such as traffic reports for a traffic Web camera

There are no Level 2 success criteria at this time. There is currently one success criterion at Level 3:
1. For multimedia content, a combined transcript of audio descriptions and captions is provided. 

Please note that WCAG 2.0 has not yet been published as a formal Recommendation of the W3C.  WCAG 2.0 is a work in progress and the text is subject to change. Working drafts should *not* be cited as normative documents.

"Good design is accessible design"
John Slatin, Ph.D.
Senior Accessibility Specialist
RampWEB, Inc.
phone +1.512.266.6189 email jslatin@rampweb.com

-----Original Message-----
From: w3c-wai-ig-request@w3.org [mailto:w3c-wai-ig-request@w3.org] On Behalf Of Jon Hanna
Sent: Saturday, May 28, 2005 1:31 PM
To: w3c-wai-ig@w3.org
Subject: Re: Text for images used as links

Vicente Luque Centeno wrote:
> WCAG 2.0 says:
>     "When an image is used as the content of a link, specify a text
> alternative for the image. The text alternative should describe the 
> function of the link."
> I completely disagree!!! The link's title (attribute) is for that
> purpose. The image's alt is just for describing the image, not for 
> describing the function of the link.

There are hardly ever cases where an images alt attribute should 
describe the image. If you want to describe the image use longdesc and 
leave alt for a textual ALTernative as intended.

> This example shows the difference between img/@alt and a/@title.
> <a href="http://validator.w3.org/check/referer" title="Validate this 
> page"> <img class="logow3c" 
> src="http://validator.w3.org/images/vxhtml-basic10.gif"
> alt="XHTML Basic 1.0 icon" /></a>

I would have coded that as:

<a href="http://validator.w3.org/check/referer" title="Validate this 
page"><img src="http://validator.w3.org/images/vxhtml-basic10.gif" 
alt="This page is valid XHTML Basic 1.0" /></a>.

Because "This page is valid XHTML Basic 1.0" is what the image conveys 
for those that can see it.

Jon Hanna

...it has been truly said that hackers have even more words for equipment 
failures than Yiddish has for obnoxious people." - jargon.txt
Received on Sunday, 29 May 2005 20:41:47 UTC

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