Re: Comment on WAI-ARIA Role: Mandatory 'describedby' Too Restrictive

response below.

Rich Schwerdtfeger
Distinguished Engineer, SWG Accessibility Architect/Strategist
Chair, IBM Accessibility Architecture Review  Board
blog: wrote on 08/22/2008 04:58:45 PM:

> Hi, ARIA folks-
> The SVG WG is discussing the use of a few specific roles for SVG
> elements, 'title' and 'desc'.  We think it would be very useful and
> appropriate to allow the role values 'description' and 'tooltip' (among
> others) on those elements.  However, both of those role values require
> [[
>   Objects with this role must be referenced through the use of a
> describedby.
> ]]
> In SVG, we are defining an algorithm that describes the relationship
> between the 'title' or 'desc' element and the element or elements they
> are describing, based on a parent-child (or more precisely,
> container-contained) relationship.  Basically, for most uses, the
> 'title' and 'desc' elements describe their parent element (which may in
> turn simply be a group of elements, in which case the general
> description applies to the collection of child elements).
> Therefore, the 'describedby' role value is superfluous and possibly
> contradictory to the well-structured solution of SVG; similarly, it is
> redundant with the HTML 'label' element, with its 'for' attribute.  For
> both these cases, the 'describedby' role may (and should) be inferred by
> the UA.
Doug, describedy is not a role. It is an attribute that references the
label and description are entirely different. Label is a short visible
label to an object.
As long as the SVG author sticks to the hierarchical structure of SVG to
associate the description
(there is a role of description) then for SVG there should be no need to
have to use
the describedby relationship and the UA can map the information to the
platform accessibility API.

However, should the author provide a description in prose elsewhere in SVG
this is where you would
want to use describedby. If we are mandating somehting already provided in
the host language I would
agree with you - "should" makes sense.

> Further, requiring this reference may discourage use of roles in these
> circumstances, by introducing arbitrary and unnecessary extra work on
> the part of the author.
> Therefore, our suggestion is that you remove this mandatory stricture,
> or soften it to a SHOULD or MAY, or describe a way in which a language
> may describe an implicit value for the 'describedby' role based on the
> host language's semantics.  You do allude to this last option in
> WAI-ARIA: [1]
Please point to the section of the specification you are referring to as
you are mixing
roles and role attributes.

> [[
> Build relationships
> ...
> Some relationships are determined automatically from the host language,
> such as by using the label tag in HTML.
> ]]
> However, you don't seem to describe the manner in which a language
> defines this, and the MUST statement in the roles seems to contradict
> the "Build relationships" wording.
> [1]
> Regards-
> -Doug Schepers
> W3C Team Contact, WebApps, SVG, and CDF

Received on Monday, 25 August 2008 15:44:51 UTC