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Re: Call for Review: HTML5 Image Description Extension (longdesc) Last Call

From: Doug Schepers <schepers@w3.org>
Date: Thu, 15 Aug 2013 18:21:34 +0000
Message-ID: <520D1C23.8020307@w3.org>
To: John Foliot <john@foliot.ca>
CC: 'James Craig' <jcraig@apple.com>, 'Charles McCathie Nevile' <chaals@yandex-team.ru>, public-html-a11y@w3.org, 'Jeanne Spellman' <jeanne@w3.org>, 'Jan Richards' <jrichards@ocadu.ca>
Hi, folks–

(Splitting into threads)

On 8/15/13 1:07 PM, John Foliot wrote:> James Craig wrote:
>>>>>> 1. @longdesc is inappropriate when an EPUB footnote is
>>>>>> sufficient.
>>>>>
>>>>> Can you explain why it is "inappropriate" in terms of the
>>>>> problem
>> that using it causes?
>
> EPUB is not HTML even if they share many similarities (i.e EPUB is
> built upon HTML5). There is no such thing however as an
> epub:type="footnote" in HTML5, and as far as I know content marked up
> like this will still render on screen, on page, which fails one of
> the use-case requirements brought forward
> (http://www.w3.org/html/wg/wiki/ChangeProposal/InstateLongdesc#Use_Cases).
>
>
> True you could perhaps hide it visually using CSS, but how would
> that help sighted users who may need the information (I know of a low
> vision user who can see infographics but hates them, and would much
> prefer to access a written equivalent).
...
>>>>> In cases where apple users are targeted it is of course
>>>>> necessary
>> to provide a fallback, since VoiceOver doesn't currently enable
>> longdesc to be used, but that is not the same as causing harm by
>> using the attribute.
>>>>
>>>> AFAIK, longdesc doesn't work in any popular EPUB reader,
>>>> unless
>> you're counting desktop browsers. Footnotes, on the other hand,
>> are well-defined and well-supported.
>
> Citation please. Which browser(s) provides an on-demand delivery of
> epub:type="footnote" content, and then allows the user to return to
> the same place in the document that provided the footnote reference
> in the first place? (See: User Choice -
> http://www.d.umn.edu/~lcarlson/research/constriants/choice.html)

I've been thinking for a while that HTML should formally introduce
markup for footnotes, which are used not only in ebooks, but on many web
pages. Wikipedia uses them extensively, for example, and they have had
to develop their own behavior for them.

As a side note, I actually quite like the way Wikipedia handles them...
they are rendered at the bottom of the screen, with a many-to-one link
in the article text, and the footnote marker (e.g., the superscript
number at the point of reference) displays the footnote text as a
tooltip when you hover over it. Academic or scientific papers also use
footnote. How they are styled and positioned should be handled by CSS,
but footnotes (and endnotes) are more than simple generic links.

That's off the main topic, but if HTML were to add footnotes (noting
that AFAIK this is not yet on the HTML WG's radar), it might have
bearing on how @longdesc is handled.


Regards-
-Doug
Received on Thursday, 15 August 2013 18:33:36 UTC

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