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RE: Not versus, but plus (was: ALT tag vs. LONGDESC)

for

From: Jukka Korpela
Date: Mar 8, 2002 1:48AM

John Foliot wrote:

> <img src="piechart.gif" height="300" width="300"
> alt="pie chart showing
> browser usage" longdesc="/longdesc/piechart.html"><a
> href="/longdesc/piechart.html" title="text description of
> user stats">d</a>

There's a lot that could be said in favor of D-links, and a lot that could
be said to criticize them. They may have their uses as interim solutions in
some situations, but in general, I'd look for more natural solutions.

An image like a pie chart assumably needs a caption text, conventionally
placed below the image. Wouldn't it then be feasible to make the caption
text a link to the textual alternative? Something like the following (sorry
for using deprecated markup, for simplicity here):

<center><img src="piechart.gif" height="300" width="300" alt=""
title="pie chart showing browser usage"><br>
<a href="/longdesc/piechart.html" title="text description of user stats">
Browser usage as measured at foo.bar.example</a><center>

In this case, alt="" would be adequate, since an empty string is an
appropriate replacement for the image. All users have the textual link at
their disposal.

One might ask whether one should try to express the most essential content
of the image in alt text, e.g. alt="99 % uses IE 6". This adds quite some
complexity into the issue, since one should then avoid giving the impression
that the _entire_ content has been expressed there.

--
Jukka Korpela
TIEKE Tietoyhteiskunnan kehitt