[Sigia-l] 508 Compliance - Alt Tags for Button Images

[P.J. Gardner]

Hi,

A short seminar on ALT text for you.

First of all, I would like to point out that screen readers for blind web
users are doing a lot to make information as clear as possible, even to make
up for sites that are not coded well.  They also have a lot of options that
users can set to their own preferences.  In JAWS, for example, (which is the
biggest selling screen reader at the moment) graphical buttons will usually
announce "Graphic Link" before reading the Alt text, assuming the user has
the verbose setting turned on.

The next thing is that blind users could care less whether it is a button or
an image used as a link.  To them the important thing is that it is a link.
The usual usability questions come up:  Where will this link take me?  What
will happen when I get there?  Will it cause me to spend money, or give my
e-mail address, or go somewhere I don't want to go?  Will it take me to
another place on the same page, to another page, or to another site?  Will
it open a new window?

JAWS will usually announce a same-page link, but JAWS 4.5.1 (which is the
current non-Beta version) does not indicate when a link goes off the site.
If you open a new window, it is a good idea to tell someone you are doing
so, because having many windows open at once can be disorienting and
cumbersome for some people, especially new computer users.  And this applies
to people with low vision using screen magnifiers even more than for expert
blind users, who use the ALT+TAB keystroke in Windows all the time.

So what do you put in the ALT attribute for IMG tags?  I disagree heartily
that you just include the same text as that on the button.  That's only one
possibility.  I think the answer is that you test with non-sighted users and
find out what they need to know.  Short of that, imagine that the page is
being read out loud over a telephone from top to bottom in HTML order
(including the alt tags where images lie) and see what information is
needed.  Or use a tool like the Lynx Viewer, which will trim things down to
an approximation of what the screen reader might be working with.  Looked at
it that way, it is quite possible that the needs may be quite different than
for sighted users.

Another thing to know is that some users turn off ALT attributes on IMG tags
and only turn on TITLE attributes (which might be applied to the A tags
instead)-- or vice versa.  TITLE attributes can be applied to almost
anything, including graphics.  The standards say that the TITLE attribute
should be supplemental, but sometimes it is the only thing that is being
heard.  Another thing to consider is that hearing a screen takes much longer
than reading or scanning the screen.  So most of the blind users I know
crank the speed way up and listen to the screen faster than I can deal with
listening as a sighted designer.  And they scan in their own way, which is
to listen to the first couple words (sometimes syllables) and decide they
are not interested and move on very rapidly.  Especially when they are on a
return visit.

[They also turn off images completely so that pages load faster, which is
not pertinent to this discussion.  Some people don't even use a monitor at
all.  But JAWS users have Internet Explorer as their browser, which is one
of the requirements of using JAWS, and you can pretty well bet they are
running Windows.  And many users are not even on the current version of JAWS
because of the expense.]

When a page contains too many links, blind users find the page tedious
(especially if every page on a site starts with the same navigational
links), so JAWS has an option built in to skip to the first contiguous text
over a certain length (which like everything else in JAWS is configurable).
I believe the default is 25 words.  Section 508 says that you should be
providing a quick way to jump over navigational links.  And you might even
want to provide ACCESSKEY attributes to provide fast access to important
links, like the stakeholder's favorite-- the "Buy Now" button.

Then there is the issue of text length.  Long ALT or TITLE text takes a long
time to read, so keeping it short is good.  ALT text should be under 150
characters max.   TITLE text might be longer, but what about the return
visitor?  I like to put verbs on mine, and I also like to put "(new window)"
at the end when I am sending someone off-site in a new browser window.  It
is definitely against guidelines, which say you should always leave users in
the same browser window.  The answer is to test with real people with
special needs, if that is feasible.  Doing that even once will teach you
more than you can imagine.

A LONGDESC refers to a separate file and can be an entire page in length, if
necessary, but it should be mostly (or completely) text-based.  The only
problem is that current browsers have no mechanism for using the LONGDESC,
so the convention is to use an A link with a small D in it for text.  Then
you can hide the D on the page with a cascading style sheet or a one-pixel
GIF (that is unless your testing with low-vision people determines that the
D should be visible.)

Clarity and the needs of users are what count, same as always.

There's a lot to think about, but it is worth it.  The people in the blind
and low-vision community gain a heck of a lot of independence in their lives
when they can use a computer screen rather than have to ask for help from
someone else to do the things I take for granted.  This is the big
opportunity.

I hope this is useful information.


P.J. Gardner
Information Designer
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Gardner Information Design, Inc.
pjgardner at GIDI.biz
www.GIDI.biz
781-646-6849
Custom & Accessible Websites
Information Delivery Strategies
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Boston-IA
info at Boston-IA.org
www.Boston-IA.org
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