Re: Another summary of alt="" issues and why the spec says what it says

On 4/20/08, Leif Halvard Silli <lhs@malform.no> wrote:

>  [Snipped the aria-describedby=idref programmatic association benefits.]

>  The aria-describedby approach adds new, hidden, meta
> information whic must be kept in order.

True.

> Instead, I'd like to propose these solution:

>  1. Reserved keywords acting as CSS selectors:
>  Elements with an ALT attribute or fallback content could have reserved
> keywords which would point to the element containing its description: A
> "_prev" keyword could point to previous element, a "_next" to next element,
> a "_parent" to the parent element.

Unfortunately, so does this -- and the burden is higher, and the
burder is higher.  It would not longer be enough to to update the
metadata when you change the element itself (or the pointed-to
element), you would also have to worry about whether someone inserted
a new element in between.

> For FIGURE, keywords are not needed and
> should not be taken account of, as long as FIGURE only contains LEGEND plus
> one single, embedding element.

WCAG agrees that this would be sufficient if it were part of the
definition of those elements.

I would still prefer to see it expressed in terms of aria-describedby,
perhaps as:

"""
If a figure contains exactly one multimedia element (image, video,
audio, or object), and exactly one textual element (caption, legend,
span, div, p), then there is a weakly implied aria-describedby
relationship from the multimedia element to the textual element.

This relationship is overridden if there is an explicit
aria-describedby relationship.
"""

and I would still like the alt (or fallback) to be mandatory unless
there is a (possibly implied) aria-describedby attribute.

-jJ