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Posted by Jukka K. Korpela on 11/23/05 00:51
"yb" <bajwa_yasir@yahoo.ca> wrote:
> I'm a bit confused about WCAG 1.0 checkpoint 7.3,
WCAG 1.0 is old, partly confused, partly outdated, and partly just too
theoretical. It's still useful, but when used as a goal in itself, it easily
becomes harmful to accessibility. Anyone who claims conformance to WCAG 1.0
for any nontrivial page is misrepresenting the truth. How could he possibly
know that he has used the _simplest language possible_, for example?
> "7.3 Until user agents allow users to freeze moving content, avoid
> movement in pages. [Priority 2]"
That's a particular bad case. It leaves the key concept undefined and uses
the nasty "until user agents..." condition.
> So, does this color fading mean this checkpoint is not satisfied.
What does movement mean on screen? It means that pixels change so that the
displayed presentation changes. Color change is thus movement. Whether the
checkpoint really means _any_ movement is and will remain an open question.
(Nobody is working to clarify WCAG 1.0. A brand new WCAG 2.0, with no real
continuity, has been under construction for a few years.)
Use your judgement, and ask people (disabled people, experts on
accessibility, or just anyone) what bothers users on web pages.
If you ask me, fading effects can be nasty, may irritate, and may make
the user wonder what's going on. Especially if there's no other than esthetic
purpose, fading should not be used, for accessibility reasons. It is then
up to you to consider how much accessibility matters in this issue.
Fading is hardly a crucial problem to any substantial amount of users.
> What
> about hovering over a link which opens up a drop down style menu? That
> could be considered movement as well.
Certainly it's movement. The real problem with it is the drop down style menu
itself. Most implementations of such features are really hostile to
accessibility. Technicalities aside, it is better to offer a well-designed
set of alternatives at a glance, visible without any particular selection,
and visible as normal link texts.
> I first thought it meant choppy movement, or blinking colors, i.e.
> something distracting and annoying.
They are surely among the worst cases, and there are specific notes on such
phenomena in WCAG 1.0. Checkpoint 7.3 is more general.
> Also, the "Until user agents .." part is also a concern. Exactly how
> would a user agent stop movement, there are so many factors.
That's one of the problems with the condition. Another problem, especially
when using WCAG 1.0 as criteria, is who decides when the time has come to say
that sufficiently many user agents do what the condition talks about.
Besides, many of "until user agents..." points should be regarded as
permanent.
Useless movement should be generally avoided - for the exact reason why it is
so popular among some groups of deeziners: it catches attention. Consider the
difficulty of concentrating on something when there's something blinking or
suddenly moving or just changing in sight. Then try to imagine how much
more difficult it would be if you had severe problems in concentrating on
anything in the first place and if your mind worked substantially slower.
--
Yucca, http://www.cs.tut.fi/~jkorpela/
Pages about Web authoring: http://www.cs.tut.fi/~jkorpela/www.html
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