Thoughts on ARIA10: Using aria-labelledby to provide a text alternative for non-text content

I wanted to share some thoughts on the proposed ARIA10 sufficient technique
for WCAG 2.



This technique relies on ARIA and has some-short term challenges.  With
ARIA techniques in general the long-term benefits must be weighed against
the current potential challenges and support by assistive technology and
browsers.



Many types of assistive technology may rely on the alt attribute to provide
the alternative text for images or images links or image buttons..  While
there are possible concerns that screen readers may speak the file name of
the image rather the associated aria label – the greater concern may be for
users of speech recognition software that relies on the alt text for direct
voice commands.  Certainly this approach then requires assistive technology
and browsers to support ARIA.  Support is wide spread but not always
consistent.  There are also many users with old versions of assistive
technology such as screen readers that may not support aria-labelledby for
images..



This technique will encourage the alternative text to be on the page
(unless some smart developer decides to hide it with CSS off the screen)  I
do like the idea of the alternative text being visible – this has always
been a bane of mine.  I have always felt that users with low vision who may
not be using a screen reader should have access to the alternative text as
they may not be able to decipher the image.  However, I am concerned that
use of aria-labelledby will encourage people to use captions as the alt text
– captions and alt text are often two different things and a caption may
not be good alt text and vice versa.



Other potential issues include issues for some automatic checkers although
these can be updated.  Automated tools are likely to flag these images as
missing alternative text.



Currently WCAG 2 does allow text alternatives to be somewhere else on a page
and not in the alt as long as the alt explains where to locate the alternative.
The definition of “text alternative<http://www.w3.org/TR/WCAG20/#text-altdef>”
in WCAG 2 is:



Text that is programmatically associated with non-text content or referred
to from text that is programmatically associated with non-text content.
Programmatically associated text is text whose location can be
programmatically determined from the non-text content.



Example: An image of a chart is described in text in the paragraph after
the chart. The short text alternative for the chart indicates that a
description follows.



Thus, the user of aria-labelledby would certainly meet this requirement of
text-alternative.  The next question is, is it used in an accessibility
supported way?



Best Regards,



Jonathan