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DESC discussion (-starter DRAFT)

From: Al Gilman <asgilman@access.digex.net>
Date: Wed, 15 Oct 1997 18:13:02 -0400 (EDT)
Message-Id: <199710152213.SAA18401@access4.digex.net>
To: w3c-wai-hc@w3.org (HC team)
Cc: jbrewer#w3.org@access4.digex.net
DESC      Text associated with images

BACKGROUND:

Images are very important to the look of most Web pages.
This naturally presents accessibility problems for people
with visual disabilities. Traditionally images in HTML pages
are specified using the IMG element, and to a lesser extent
with the form field INPUT element for image fields (type=image).

For both of these elements, authors can provide a short
description with the attribute named "alt". Most authoring
guidelines recommend authors to use this feature. HTML 4.0
makes this a required attribute.

Whats missing is an ability to specify a longer rich text
description for images -- a richer description that can
include headings, paragraphs, lists and hypertext links etc.
This is especially critical for images that are being used
for image maps.

PROPOSAL:

HTML 4.0 introduces a new element named "object" for embedding
images and other objects into HTML pages. Unlike IMG, object
is a container that wraps around the alternative content to
be used when the object itself can't be rendered directly.
We are hoping that authors will switch from IMG to OBJECT over
a period of time.

Many people take a long time to upgrade to newer browsers. As a
result, Websites design their HTML pages to look good on older
browsers as well as the latest models.  The OBJECT element is
not upward-compatible with the behavior of existing browsers.

As a result, the IMG element will be in use for a long time to
come, and we still need to find a way for authors to make IMG
more accessible. The proposed solution is to add a new attribute
named "longdesc" that can be used to provide a URL pointing to a
longer description. This will in most cases be placed in a
separate file. People using say speech-based browsers will first
read the alt attribute and then choose whether to follow the link
provided by the longdesc attribute.

In addition, the TITLE and LONGDESC attributes should be possible
on FRAME and IFRAME elements, because these elements are often
images or graphical layouts benefiting from a text alternative
and/or explanation.

QUESTIONS:

Can an IMG have both a USEMAP and a LONGDESC?  What would you use
this combination for, and how should this be handled by browsers?

What are the pros and cons of putting a LONGDESC on an IMG versus
hard-coding a link to the description in the page?

FOLLOW UP:

Please discuss this issue by sending email to w3c-wai-ig@w3.org .
Include the symbol DESC in the subject heading of your message,
to help other subscribers organize the volume of mail we hope
this will generate.
Received on Wednesday, 15 October 1997 18:13:26 UTC

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