spaces and alt-text. proposal for the ERT.

Hi all,

I think GL is done debating about what to use as alt-text.  It seems that 
we would  rather be encouraging authors to use style sheets for 
positioning.  While I agree with this, it is not entirely realistic today 
due to the inconsistent support for CSS positioning.  Therefore, I propose 
the following for the ERT document:

1.  Images with alt="", alt=" ", and alt=" " (or alt=" ") should 
be flagged.

2. If the image is part of a link that has text (e.g., <a 
href="home.html"><img src="button.gif" alt=" ">Refer to our home page</a>) 
this is o.k.

3.  If the image is not part of a link, query the author for the use of the 
image.

3a. If the author identifies the image as a space between words and those 
words should not be separated, advise them to use &nbsp; (or alt="&#160;") 
instead of an image.

3b. If the image is purely decorative and has no meaning to the content of 
the page, advise them to provide a brief descriptive text and suggest that 
they may also want to link to a longer description of the image with the 
"longdesc" attribute.

Exceptions to this rule are image effects that could be created with style 
sheets, such as graphical list bullets.  Advise authors to use style 
sheets.  (See examples in the WCAG 1.0 Techniques document)

3c.  If the image is a space that is used to format the layout of text, 
advise them to use style sheets or alt=" ".

3d.  If the author indicates the image has a function, advise the author to 
provide a functional text equivalent and if necessary link to a longer 
description.

Any further thoughts from GL?  I am also including the last message on this 
thread, sent by Jason White on 18 November.
--wendy


>Resent-Date: Wed, 17 Nov 1999 18:20:58 -0500 (EST)
>Date: Thu, 18 Nov 1999 10:20:20 +1100 (EST)
>From: Jason White <jasonw@ariel.ucs.unimelb.EDU.AU>
>To: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
>Subject: Re: proposal for "null" alt-text (was "Re: GL's 
>interpretation   of    null alt-text")
>Resent-From: w3c-wai-gl@w3.org
>X-Mailing-List: <w3c-wai-gl@w3.org> archive/latest/2549
>X-Loop: w3c-wai-gl@w3.org
>Sender: w3c-wai-gl-request@w3.org
>Resent-Sender: w3c-wai-gl-request@w3.org
>
>I agree entirely with Nir's position: it is better to advise authors to
>use more appropriate techniques, particularly CSS, than to waste time
>debating the merits of various text equivalents for so-called "spacer
>images". Since this issue originally arose as a query from the ER working
>group, our answer should suggest that all uses of null and blank ALT
>attribute values (alt="" alt=" " and alt="&nbsp;" etc.) should be flagged
>as errors, with ALT="" being a more serious error than either of the
>others.
>
>The HTML specification does not determine how user agents will or should
>render ALT=" ". It may be interpreted as a single-character attribute
>value, comprising a space, or either leading or trailing white-space, to
>be ignored during HTML processing, preceded or followed by the empty
>string. As Nir has pointed out, the rendering of so-called "spacer
>images" is subject to variation across distinct visual media and among
>different user agents. The rendering of the text equivalent in these cases
>is equally undetermined, as the present controversy has shown. In the end,
>authors who wish to misuse HTML in an attempt to achieve formatting
>effects run the risk of having their documents rendered in unexpected ways
>by different user agents and/or in different media. Such practices should
>be avoided.

<>
wendy a chisholm (wac)
world wide web consortium (w3c)
web accessibility initiative (wai)
madison, wisconsin (madcity, wi)
united states of america (usa)
tel: +1 608 663 6346
</>

Received on Monday, 6 December 1999 16:15:44 UTC