HI Debi,
On Aug 28, 2007, at 10:34 AM, Debi Orton wrote:
Hello,
We (the NYS Forum IT Accessibility Committee) did some work last
year that indicated that screen reader users fell into two camps
with regard to the usefulness of alt attributes for images. Some
users wanted to know what EVERY image was so that they could be
sure they weren't missing information. Others wanted only
meaningful images described. We proposed an additional attribute
(two values only) for the img element to indicate whether the image
was informational or just eye candy.
This sounds very much like a proposal discussed earlier on the list.
Just to summarize, it evolved through the discussion (and still needs
to be added to the wiki), but basically it involves using the @role
attribute to indicate whether an image's role in a document with
newly introduced keywords: 1) 'decorative', 2) 'icon', 3)
'seefallback', and 4) 'seecontext'. While all embedded content would
be required to have a role attribute with one of these four keywords,
for embedded content with keywords 'decorative' or 'seecontext', no
@alt attribute would be required. It could be alt='' for backwards
compatibility.
For those cases where the keyword was set to 'seefallback' or 'icon'
the @alt attribute would be required with a meaningful and non-empty
string. My view is that we should recommend that conformance checkers
provide an option for authors to suppress @alt @role errors and
warnings (a selection that is not persistent between sessions) so
that authors do not simply circumvent the conformance checker by
adding bogus @alt or @role values (e.g., adding 'decorative' when the
images are not decorative). The often mentioned noalt attribute would
be the same as having a @role value of 'seefallback' or 'icon' and
having no fallback content (this is for any embedded content element
so @alt is just one of the relevant fallback mechanisms).
An embedrel DOM attribute would provide an API to access the relevant
values and make this approach compatible with pre-HTML5 content. This
approach allows users to discover the role of the embedded content
and explore at their own option richer descriptions depending on the
role of the embedded content.
Take care,
Rob
[1]: <http://lists.w3.org/Archives/Public/public-html/2007Aug/0647.html>
