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Re: rationale for role=presentation use on images

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Thu, 15 Jul 2010 06:42:52 -0500
Message-ID: <AANLkTinyii7Sm5EzA8cI7G9r7fEXTL3rhU5nubzIgMmm@mail.gmail.com>
To: Steven Faulkner <faulkner.steve@gmail.com>, Maciej Stachowiak <mjs@apple.com>, Sam Ruby <rubys@intertwingly.net>, Paul Cotton <Paul.Cotton@microsoft.com>
Cc: HTML Accessibility Task Force <public-html-a11y@w3.org>
Hi Steve and all,

Thank you very much for providing rationale for role="presentation". I
updated the change proposal to include it.
http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20090126#role.3D.22presentation.22_Attribute

Maciej, please re-add this change proposal to the change proposal
table for HTML ISSUE-31.

Thanks.

Best Regards,
Laura

On 7/15/10, Steven Faulkner <faulkner.steve@gmail.com> wrote:
> Hi Laura,
>
> role=presentaion can be placed on any element to indicate that it should not
> be included in the accessible tree by the browser.
> It is intended that user agents do not expose the element role via
> accessibility APIs when role="presentation" is present on an element.
>
> In HTML5 as per the current spec alt="" [1] on an image has an implied ARIA
> role of presentation, although current implementations do not honour this.
> use alt="" does not result in the img being removed from the accessible tree
> by browsers. AT recognise alt="" as indicating that the image can be safely
> hidden from the user, but their ways of handling this are not uniform.
>  So in the spec role="presentation and alt="" are equivalent. Allowing
> role="presentation" to be a conforming replacement for alt="" just
> recognises what the spec states.
>
> Why allow role="presentation" to act as an alternative to alt=""?
> it is specified and implemented to do what alt="" is specified to do.
> It is non specific, it works on all elements.
> As per the rules specified in current spec pertaining to its use [1]  the
> use of role="presentation" is not dis-allowed on the img element it is in
> fact stated that it is the only role that can be applied to an img that has
> an alt="", so you can do this:
>
> <img role="presentation" alt="">
>
> and nowwhere in the aria section [1] does it state you can't do this:
>
> <img role="presentation">
>
> but it will result in a conformance error, which appears both incongruous
> and illogical.
>
>
> [1]
> http://dev.w3.org/html5/spec/content-models.html#annotations-for-assistive-technology-products-aria
>
> --
> with regards
>
> Steve Faulkner
> Technical Director - TPG Europe
> Director - Web Accessibility Tools Consortium
>
> www.paciellogroup.com | www.wat-c.org
> Web Accessibility Toolbar -
> http://www.paciellogroup.com/resources/wat-ie-about.html

-- 
Laura L. Carlson
Received on Thursday, 15 July 2010 11:43:23 GMT

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