Conveying metadata unobtrusively in HTML

Colour - and other visual styling - is a great tool for conveying
information.  For example, if we are evaluating something, we may
use red to highlight an error, amber for a warning, and green for OK.
But of course, that raises the obvious accessibility issue for the
visually impaired.

In Page Valet, visual information is duplicated in text: in particular,
accessibility messages are prefixed with, for example, "WCAG2/High"
to indicate a WCAG level 2 checkpoint that we have diagnosed with
a high level of certainty.  This is visually obtrusive, and I don't
really like it.

Another option I'm playing with is to abuse the "title" attribute
for this kind of thing.  The logic is that this becomes unobtrusive
for visual users, but accessible to non-visual devices.  It's not
really right: technically there isn't a better mechanism in HTML,
but an equivalent scripting solution is likely to be horribly
long-winded and less well supported by assistive devices.

I have a new service in preparation, and have just opened the first
preview prototype at <URL:http://valet.webthing.com:8000/html-form.html>.
This uses the title technique to highlight whether an attribute is
valid, deprecated or bogus, duplicating visual information conveyed
by colour.

Comments please: is this technique a reasonable approach to the problem?
Can anyone suggest a better approach?


-- 
Nick Kew

Available for contract work - Programming, Unix, Networking, Markup, etc.

Received on Sunday, 2 June 2002 18:10:33 UTC