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Re: Working Group Decision on ISSUE-31 / ISSUE-80 validation survey

From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Date: Tue, 19 Apr 2011 01:30:54 +0200
To: Aryeh Gregor <Simetrical+w3c@gmail.com>
Cc: Maciej Stachowiak <mjs@apple.com>, HTMLWG WG <public-html@w3.org>
Message-ID: <20110419013054565948.692f30da@xn--mlform-iua.no>
Aryeh Gregor, Mon, 18 Apr 2011 18:35:16 -0400:
> On Mon, Apr 18, 2011 at 4:33 PM, Maciej Stachowiak <mjs@apple.com> wrote:
>> After considering all these arguments, it seems established that there
>> is a valid use case for allowing the alt attribute to be omitted when
>> the generator mechanism is specified. This use case makes for a
>> moderately strong objection. However, the claim of negative
>> consequences to disallowing this use case was somewhat weakened by the
>> lack of concrete evidence that bogus values have been used in the past
>> or would be used in the future.
> 
> [...] I'd like to provide some concrete evidence on this point,
  [...]
> the two images on the bottom right all have alt="":
> 
> http://en.wikipedia.org/w/index.php?title=Cwm_Penmachno&oldid=383061670

> Since no alt text was provided using the "|alt=" parameter, empty alt
> text is automatically inserted so that the page validates.  In older
> MediaWiki versions, the caption would be repeated in the alt text,
> leading to the caption being read twice by screen readers -- again,
> the motivation being to ensure that it validates.  This was changed to
> empty alt text so that at least it wouldn't be repeated.
> <https://bugzilla.wikimedia.org/show_bug.cgi?id=368>

According to HTML5's current rules (before the Decision has been 
applied, and hopefully after it is applied as well), then: [1]

]] When an a element that creates a hyperlink, or a button element, has 
no textual content but contains one or more images, the alt attributes 
must contain text that together convey the purpose of the link or 
button.[[

Due to the lack of @alt text, VoiceOver currently tries to repair by 
reading aloud the URL of the anchor element wrapper.

[1] 
http://dev.w3.org/html5/spec/embedded-content-1#a-link-or-button-containing-nothing-but-the-image
-- 
leif halvard sillli
Received on Monday, 18 April 2011 23:31:25 UTC

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