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RE: Support for LONGDESC

From: Jon Hanna <jon@spin.ie>
Date: Tue, 6 Aug 2002 11:52:12 +0100
To: <w3c-wai-ig@w3.org>
Message-ID: <NDBBLCBLIMDOPKMOPHLHGEGEEEAA.jon@spin.ie>

> Also what formats can the longdesc file be in?
[snip]
> But doesn't say whether the file can be HTML, XHTML, plain text, etc.
> (or that it shouldn't be PDF, GIF, etc.!), can contains JavaScript, etc.
> Although the example give a file with a .html extension.

All of those would meet the spec, but obviously some would be more advisable
than others.

I would recommend a backwards-compatible XHTML page (since it's reasonable
to assume the reader can handle such a format, having arrived there from an
HTML page (X- or otherwise). I would recommend that the page included the
image being described, which should be linked to itself and have an alt of
"download the image" or similar, so that a user who can see the image but
wants to read the longdesc anyway can see it in that context, and so that a
user who can't see the image can download it to either view in a separate
viewing application (say a sighted user of Lynx), pass it to a sighted
colleague, examine the file itself (the octets rather than the picture) or
whatever they want.

I'd also recommend providing both a description of the picture, and of the
file, but keeping the two very clearly separated in the description, since
it's reasonable to assume that some would be interested in the former, and
some in the latter.

> If use of longdesc is needed to future-proof Web resources for when
> browser support is available, are their any guidelines on using
> longdesc?

There is some browser support already, Mozilla1.0 provides a link to the
description of an image when you opt to view that images properties. I would
not be surprised to learn that search engines which provide the option to
search for an image use it as part of their discovery mechanism.
Received on Tuesday, 6 August 2002 06:51:17 GMT

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