Add deprecation warning to longdesc technique

[joppekroon]

The section on complex images mentions the longdesc attribute as a potential technique. However, MDN warns that the longDesc attribute is obsolete.

Assuming, MDN is correct, I think it would be appropriate to warn would be implementers that this technique is deprecated (besides spotty in it's implementation).

The MDN article goes on to recommend wrapping the image with an anchor element as a replacement. I'm not sure that that would be a real replacement for the semantics that longDesc would provide, but maybe also something to address?!

[yatil]

Longdesc is an official W3C Web Standard (as a HTML5 Extension) and not deprecated in HTML5: https://www.w3.org/TR/html-longdesc/

[joppekroon]

So it is. MDN is incorrect then.

I opened a similar issue on the H45 technique in the w3c/wcag repo. Although the initial response was the same, the discussion is still ongoing there due to the support being quite bad/ getting worse.

Would you prefer to close this issue, or wait for a conclusion in the H45 thread?

[JAWS-test]

Even if longdesc is not obsolete, I am in favor of not recommending it and thus removing it in the tutorial.

• AT support is bad
• For cognitive and visual impaired people is not or hardly recognizable that there is a detailed description. A link below the picture would be much better.

[yatil]

The support for longdesc has actually improved marginally with Firefox now displaying it in the context menu. The tutorials have been constructed to give multiple approaches and the longdesc one is the last one. The most straight forward and widely supported technique (a link to the long description) is mentioned as “Approach 1”.

This was long deliberated in the Education and Outreach as well as the Accessibility Guidelines Working Groups who back then strongly supported mentioning longdesc.

I’m personally open to removing it from the page. We want to start working on addressing issues on the tutorials soon and w3c/wcag#950 can certainly advise with the decision for the tutorials. (I.e. the tutorials are currently just reflecting a selection of WCAG techniques, if a technique was removed, it would likely be discouraged to mention this technique in tutorials.)

[yatil]

I’ll lock the conversation here for now to channel it in w3c/wcag#950. Once there’s a decision over there, I’ll see to reopen the conversation on how to approach addressing the decision in the tutorials.