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Re: ARIA style sheet

From: Chris Blouch <cblouch@aol.com>
Date: Wed, 25 Feb 2009 10:30:11 -0500
Message-ID: <49A56403.2080809@aol.com>
To: James Craig <jcraig@apple.com>
CC: Chris Blouch <chris.blouch@corp.aol.com>, "'W3C WAI-XTECH'" <wai-xtech@w3.org>
I need to make a retraction in that the actual author is Stuart 
Langridge who came up with the solution in response to a presentation by 
Matt Machell. That said, Stuart has posted some clarity on what his 
solution is and is not. I believe he argues for himself more clearly 
than I did:



James Craig wrote:
> Chris Blouch wrote:
>> I think Matt Machell wasn't saying so much that role:slider was a 
>> style but that we should embrace using something like CSS selectors 
>> to map one or more DOM nodes to one or more sets of ARIA attributes. 
>> Call it a shorthand way to add semantics.
> For roles, states, and properties that JavaScript will not need to 
> control, this makes sense, and is the intended purpose of mapping ARIA 
> to an implementing host language like HTML 5. For example, if a user 
> agent mapped @required in HTML 5 directly to the same API as 
> @aria-required, then the need to do this via a shorthand is 
> irrelevant. Likewise, there is no need to use role="heading" on a 
> heading element like html:h2.
> For widgets that JavaScript does need to control, I'd be wary of 
> assigning them via a technology other than JavaScript, because if 
> JavaScript is unavailable, the author won't be able to comply with 
> their end of the ARIA contract for managed widgets. Assigning ARIA 
> semantics through a technology like XBL [1] or Behavioral Extensions 
> to CSS [2] is a good topic to discuss for ARIA 2.0. I added it as an 
> ARIA2 issue [3].
> ISSUE-119: Consider use of a technology like XBL or BECSS to assign 
> ARIA semantics (roles/state/props) and event handlers
> 1. http://www.w3.org/TR/xbl/
> 2. http://www.w3.org/TR/becss/
> 3. http://www.w3.org/WAI/PF/Group/track/issues/119
>> If I have 20 sliders and each one is a constructed by a <div 
>> class="slider"></div> it seems systemically wrong to have to put in 
>> all the ARIA attributes inline repeatedly whether by hand or via a 
>> dom walking script.
> I agree with you that you shouldn't have to do it by hand, but I don't 
> think I agree with you about not using the DOM walking script, 
> especially for widgets that the JavaScript will need to control.
> The example I listed in the thread uses checkbox as an example, but 
> you could also use a similar method for complex managed widgets like a 
> tree control. For example, this script would assign the 'treeitem' 
> role to any html:li elements within a node using a 'tree' className. 
> You'd need some additional code for the tree role itself, as well as 
> for any sub-level group nodes and appropriate even handlers, but the 
> idea is the same, and can be accomplished using standard JavaScript or 
> a technology like XBL.
> for (/* each li elm within a node with a 'tree' class, using $$('.tree 
> li') */) {
>   elm.setAttribute('role', 'treeitem');
>   /* note: example uses the Prototype.js hasClassName shorthand */
>   if (Element.hasClassName(elm,'expanded')) 
> elm.setAttribute('aria-expanded','true');
>   else elm.setAttribute('aria-expanded', 'false');
> }
> <ul class="tree">
>   <li>One</li>
>   <li>Two
>     <ul>
>       <li>A</li>
>       <li>B</li>
>     </ul>
>   </li>
>   <li>Three</li>
> <//ul>
>> We should have a means to infer the applicable ARIA semantic 
>> attributes from the already stated class or other other fingerprints 
>> defined by the selector. Maybe the problem is folks call them CSS 
>> selectors when really they could be used for broader purposes. 
>> Imagine all the handy stuff the selector cascade process could do to 
>> auto-generate appropriate ARIA markup for the same generalized chunk 
>> of HTML based on the context of its location in the DOM. All those 
>> joys and challenges of specificity could be made to work for ARIA as 
>> well.
> Selectors can be made to work for ARIA today. Most JavaScript 
> libraries have a "get elements by selector" method like the example 
> used above. $$('.tree li')
Received on Wednesday, 25 February 2009 15:30:58 UTC

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