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Comment for UA implementation guide section 4.6.1.1 Text Alternative Computation

From: Sofia Celic-Li <sofiacelic@gmail.com>
Date: Tue, 15 Jun 2010 11:33:49 -0700
Message-ID: <AANLkTil3MvYEe1NP-g8h0pfTpFA1w9Vp7af_K-fGOcKl@mail.gmail.com>
To: public-pfwg-comments@w3.org
The online form did not allow submission with my email address, so sending
this comment to the list.


Comment:

One of the areas that I have not been able to find a sufficient
implementation solution for is labeling of form controls that need to
reference external text as well as themselves via the aria-labelledby
attribute. That is, the aria-labelledby attribute requires a list of values
that reference text external to the form control as well as the form
control's own title or aria-label attribute value.

While the aria-labelledby attribute is supported in later versions of screen
readers such as JAWS, it only works with references to external labels and
currently only if the form control does not have a title attribute (or,
presumably, an aria-label attribute when this is supported). Attempting to
reference the form control's title or aria-label attribute value (via
referencing the form control's ID value) is not supported. It would seem
that the current hierarchy imposed by the computation rules would not allow
such a concatenation of labels.

This means that I am back to using hacks that were used pre-ARIA. I am
required to either place all of the information in the title attribute value
(repeating text that is already present in the page) or I include a hidden
version of the form control's original title value (by hiding it off
screen). Neither of these should be necessary and ARIA has then failed to
improve this implementation issue. Also note that in this scenario a change
in design for the general audience is not desirable.


Proposed Resolution:

I am proposing a slight change in order for the computation rules.

The aria-labelledby attribute would be first in the preference hierarchy and
allowed to reference its own element (via ID) in order to add a value
provided by an attribute lower in the hierarchy - either from aria-label
and/or from an appropriate attribute allowed by the technology in use (such
as title or alt). Limiting parent attribute referencing to attributes lower
in the hierarchy prevents a loop.

If the aria-labelledby attribute is missing or empty then use aria-label;
and so forth as per the hierarchy outlined in the current draft.

The text for 4.6.1.1 part 2A would be:

Authors *MAY* specify an element's text alternative in content
attributes<http://www.w3.org/TR/2009/WD-wai-aria-implementation-20091215/#def_attribute>,
used in this order of preference:

   - The aria-labelledby attribute, which joins referenced substrings, takes
   precedence as the element's text alternative. The attribute can reference
   its parent element in order to add a value provided by an attribute lower in
   this preference list (this prevents aria-labelledby from referencing
   itself). The text alternatives for all the elements referenced will be
   computed using this same set of rules. User agents will then trim whitespace
   and join the substrings using a single space character. Substrings will be
   joined in the order specified by the author (IDREF order in the
   aria-labelledby attribute).
   - If aria-labelledby is empty or undefined, the aria-label attribute is
   used.
   - If aria-labelledby and aria-label are empty or undefined, check for the
   presence of an equivalent host language attribute or element for associating
   a label, and use those mechanisms to determine a text alternative. For
   example, in HTML, the img element's alt attribute defines a label string
   and the label element references the form element it labels.



Thank you for taking the time to consider this late submission of feedback.

Sofia Celic-Li
Received on Tuesday, 15 June 2010 18:34:25 GMT

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