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Re: additional sentence for 204

From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Date: Fri, 14 Sep 2012 03:02:49 +0200
To: James Craig <jcraig@apple.com>
Cc: Janina Sajka <janina@rednote.net>, Cynthia Shelly <cyns@microsoft.com>, HTML Accessibility Task Force <public-html-a11y@w3.org>, Ted O'Connor <eoconnor@apple.com>
Message-ID: <20120914030249212499.ceaedd1e@xn--mlform-iua.no>
I will also mention that HTML5 has an <map> example which contains both 
<a> elements and <area> elements, the intention of which is that the 
former can function as navigation links while the <area> elements can 
be used for a - navigational - image map. 

http://dev.w3.org/html5/spec/the-map-element.html#the-map-element

Obviously, such <map> would not have hidden="", or else it would not 
have any point to sighted users. But is there are risk that a "helpful" 
AT, when presenting the image map, could *first* read the <area> links, 
and then continue with the other links? And is it certain that AT 
*ignore* "lose" <area> that they find inside <map> - or wherever?

What I am aiming at is: Does hidden="" imply "description" as well, so 
that adding hidden="" increases the chance that the AT would present 
the content of <map>?

Leif H Silli

Leif Halvard Silli, Fri, 14 Sep 2012 02:45:41 +0200:
> Comments on James's variant of the text.
> 
> ]]
>  Note: Only hidden="" elements that are referenced indirectly by a 
>  unique identifier (ID) reference
> 
> [What about @name for <map>?]
> 
>  or valid hash-name reference may 
>  have their structure and content exposed upon user request. Authors 
>  desiring to prevent user-initiated viewing of hidden="" elements 
>  should remove identifier (ID) or hash-name references to the element.
> [[
> 
> So now I want to defend HTML: This sounds much too ARIA like in its 
> logic.
> 
> When it comes to aria-describedby/-labelledby then they do not imply a 
> particular semantic relationship between the two connected elements: 
> labelledby could refer to a <caption> but it could also refer to a 
> <div> - even a <script>.  By contrast, take for instance the @usemap 
> attribute. If you remove it, then you remove the entire image map 
> functionality. For all users. Even AT users.
> 
> For the @headers attribute your logic could seem simpler to accept as a 
> hidden <th> element does not affect anyone. However: It would be 
> possible to use @headers to create some CSS or JavaScript that 
> highlights the referenced headers. And @headers do define which the 
> connected header cells are *even if they are hidden*. So by removing 
> @headers, one would be changing the semantics of the table.
> 
> I am of course not opposed to *inform* the spec readers that hidden 
> elements are not revealed to anyone if either the referenced attributes 
> ( @id, @name) or the referencing attributes (@headers, @usemap and 
> others) are removed. But I am opposed to "informing" readers that this 
> is a method they can use in order to prevent hidden text from being 
> read. To say that, is a much too simplistic.
> 
> Ultimately, what you say here is that if someone uses @longdesc to 
> point to somewhere in the same page, then the spec should inform 
> authors that they can prevent the referenced text from being presented 
> by removing the @longdesc. Is there really a point in saying such a 
> thing?
> 
> I am afraid that we cannot 100% solve this dilemma without counting on 
> ARIA. For example, imagine that the <map> element contained some ASCII 
> art. Then, remember that we are talking about a situations where the 
> "full semantics" are present. So then it would be possible to use 
> role=img on the child element containing the ASCII art. One could also, 
> I suppose use aria-hidden="true" inside e.g. a <map>. If the text "must 
> not" talk about this, then it should say that "HTML has no means for 
> hiding such content, but that authors may use ARIA attributes, see 
> ARIA". 
> 
> I am not sure that we even need to talk about id references - it sounds 
> like language that has been placed there to prevent something in the 
> future or whatever. But what about the <object> element. Or <canvas> ? 
> Is the fallback/subdom of <canvas> considered hidden? If you add 
> hidden="" to an element inside <canvas>, does that change anything? If 
> that change anything, then I agree that the subdom of <canvas> is not 
> hidden and as such falls outside the subject. But what about <object>? 
> Remember that <object> can be image maps. And that the <map hidden="" 
> name="map" > element then can be placed as child of <object>. Is it 
> only when <object usmap="map"> contains a <map> that its fallback will 
> be rendered with full semantics?
> -- 
> leif halvard silli
> 
Received on Friday, 14 September 2012 01:03:19 GMT

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