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RE: Alt tags

From: Jon Hanna <jon@spinsol.com>
Date: Thu, 6 Sep 2001 10:48:37 +0100
To: <w3c-wai-ig@w3.org>
Message-ID: <NDBBLCBLIMDOPKMOPHLHAEHPDHAA.jon@spinsol.com>
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> 1. Is there any way to choose where to place an alt tag in relation
> to the image it is describing or does it always appear just below
> 'the hand'?  
> 
> 2. Can you control the length of time an 'alt' tag appears
> onscreen?  
> 
I think you are confusing the intention of alt tags with the way some
graphical browsers render them. The primary intention is for use with
browsers or browse-reader combinations where the graphics do not
"appear" at all. Some graphical browsers decided to use the alt text
as a toolTip/Balloon Help text as well. This idea wasn't terrible (it
can aid comprehension) but it wasn't great either as the best alt
text is not necessarily also the best toolTip text, and at times when
the image is self-explanatory to those who can use them the toolTip
is a mere nuisance.
I've long considered this a design flaw, and it has lead to many
designers who work primarily with graphical browsers using alt text
that works well as a toolTip whether it works well as alternative
text or not.

HTML4.0 introduced the title attribute which provides information
about any visible element (<body> and most elements that go inside
it) and suggests that graphical browsers use this as a toolTip. IE4+
does so and it over-rides the alt text for this purpose (At least
some versions of IE5 have a flaw where it doesn't override alt for
this purpose on <area> elements).

To directly answer the questions, there is no way to control the time
or position of the toolTip, although you could instead use dHTML
methods to produce the same effect - but this opens a whole slew of
rather difficult accessibility issues. You can also do some funky
ActiveX stuff with toolTips, but this has accessibility AND security
issues, and is a lot of work.

> 3. Does anyone have any alternative suggestions to the 'alt' tag 
> for the nav
> items (which at this point must remain as images).

Alt is the way to go. However you may like to have slightly different
text in the title attribute, or perhaps title="" (to kill the toolTip
on those browsers that support it, but keeping the alt for text-based
users).

> 4. There have been instances when surfing that 'alt' tags have 
> appeared, yet
> when images are turned off some do not get labelled with their
> alternative text.  Does anyone know why this occurs?  See
> http://www.aahc.com.au/  

This relates to how graphical browsers display alt text visually with
images turned off in the position that would hold the image if they
were turned on. Often the alt text doesn't fit in the "place-holder".
Some browsers have an option to stretch the image place-holder to
accommodate the alt text when images are turned off, but even then it
often doesn't work correctly. At the end of the day those browsers
were designed to display images, not alt text.
That is the case on the page you give. This doesn't affect users of
text-only browsers, who always get the alt text, and I understand
(but am open to correction) that it doesn't affect users of graphical
browsers with screen-readers.

I would suggest that some of the alt-text actually be removed on that
page. On a text only browser "Animal Health Australia cow Animal
Health Australia sheep Animal Health Australia rotating images Animal
Health Australia" isn't much use. Most of those images are for
decoration and replacing their alt text with "" would probably be the
best solution.

Similarly I'd change "Animal Health Australia Logo" to "Animal Health
Australia", so the alt text seen by text-based users more closely
matches how the logo is read by users of graphics.

The menu alt text is perfect IMHO. You may wish to use title="" if
you don't like the toolTips as the images seem quite clear and
readable and I imagine would prove little difficulty to poor-vision
sighted users. However I'll bet you a shilling someone on this list
will prove me wrong :)

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Received on Thursday, 6 September 2001 05:46:23 GMT

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