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Re: Keyboard support and ARIA

From: Charles McCathieNevile <chaals@opera.com>
Date: Sat, 01 Aug 2009 18:40:09 +0200
To: "Simon Harper" <simon.harper@manchester.ac.uk>
Cc: "Henny Swan" <hennys@opera.com>, "WAI-UA list" <w3c-wai-ua@w3.org>
Message-ID: <op.uxzm07xtwxe0ny@pc162.lan028.oslo.opera.com>
On Fri, 31 Jul 2009 15:48:16 +0200, Simon Harper  
<simon.harper@manchester.ac.uk> wrote:

> Hi there,

First, I would like to continue the discussion in one place if possible -  
itis very hard for me to track multiple mailing lists and see any  
consistency, so we end up going around the same circles 10 times instead  
of making progress.

If you are subscribed to wai-xtech, please reply to the original post  
there...

> thanks for the clarification - one thing I had in mind was the  
> definition of a 'web' modifier key - say function lock, which modifies  
> the OS keyboard scan codes, in this way I would expect the OS/Browser to  
> understand which keystokes are intended for which platform. I don't  
> think this will be solved my just web tech - but I do think that the  
> likes of Google will be expecting to create a clean and holistic  
> experience for their chrome os and the web apps that sit with it;  
> likewise (maybe) for Apple Web Apps. Once we think of a webapp as just  
> software we can see that the keyboard, and assignments of key  
> combinations, are really internationalisation issues and we can allow  
> local assignments based on language setting and semantics of the  
> key_action assigned - however encouraging web designers to have free  
> range with ad-hoc key combination (accesskeys+js) assignments is a  
> mistake in my opinion. Having a well defined way of doing this would be  
> better.

Opera has been using the web as a software platform for a long time now -  
this proposal comes in large part from that experience.

Accesskey, unlike pure javascript, doesn't leave things in the hands of  
the page author. The accesskey attribute does two things.

First, it identifies a particular control (link, form control, something  
activated by javascript) as important enough to have a direct access  
method.

Second, it provides a *suggestion* for how that direct access method might  
be memorable to the user.

(Contrast this to tabindex, which only identifies something as active and  
therefore something the user must be able to get to and activate, even if  
it's a list item or other not normally active element).

In any intelligent implementation, the user agent and the user both have  
the ability to change the activation method. An important consequence of  
this is that the author shouldn't try to explain the activation method -  
that's the user agent's job, and acceskey implementation should be  
consistent across a given user agent for all pages, rather than being  
dependent on the particular web-page. This is critical to allow it to work  
on a variety of devices.

The use of plain javascript instead is common today in order to make  
things look like nice applications. This is a problem in trying to port  
stuff written for a single system, rather than the web, to different  
browsers and platforms. The challenge is to work out how to make it easy  
to have a nice interface, while not interfering with what the user expects  
the browser to do (the big problem with most old-fashioned accesskey  
implementations).

> Heck can HTML5 just not include an 'action' attribute with a defined set  
> of opcodes to facilitate localisable control. I agree about the number  
> you could have but touch gestures, haptic gestures, and key modifier  
> codes could be included - it will take time for HTML5's uptake.

There is a "command" concept in HTML that does something like this  
already. But no, it is not going to be feasible to include a sufficient  
number of opcodes as activation handles (those that can be listed sensibly  
should be aria-roles or rel values, actually).

So the accesskey attribute, which allows the author to suggest a key, is  
what you are asking for. In HTML 5 it has a few benefits over the HTML 4  
version - first, the terribly bad advice about implementation has been  
removed, second, it defines a DOM attribute so script can find out what  
actually does activate the control in question.

> Cheers
> Si
>
> On 31 Jul 2009, at 16:13, Charles McCathieNevile wrote:
>
>> On Fri, 31 Jul 2009 14:54:59 +0200, Simon Harper  
>> <simon.harper@manchester.ac.uk> wrote:
>>
>>> Thanks for that Henny,
>>>
>>> One think comes to mind, could we not mark up elements that can enact  
>>> programmatic events with explicit 'action' semantics. Such as:
>>
>> Between the use of ARIA roles, and @rel values, we have a fair amount  
>> of information about common patterns already. It is not feasible to  
>> provide default keyboard shortcuts for a huge set of things - when you  
>> have a keyboard like Opera mini usually encounters, even using key  
>> combos you have 30 things you can assign, and most of those are given  
>> to the UI or common links already. (Actually iPhone's gestures, and  
>> mouse gestures in Opera, have a similar role in life and similar  
>> limitations in numbers).
>>
>> But where there are common ways to describe common semantics, making  
>> things that are an explicitly keybaord-controllable function is better  
>> than just listening for various javascript events. And using things  
>> like tabindex and accesskey (which although they are still sub-optimal  
>> in implementation are no more broken than mysterious key-trapping in  
>> javascript) is a step forward too.
>>
>>> <ul>
>>> 	<li><a id="ks_file">File</a><li>
>>> 	<ul>
>>> 		<li><a id="ks_tab">New Tab</a><li>
>>> 		<li><a id="ks_file">Open File</a><li>
>>> 		<li><a id="ks_location">Open Location</a><li>
>>> 	</ul>
>>>
>>> 	<li><a id="ks_edit">Edit</a><li>
>>> 	<li><a id="ks_help">Help</a><li>
>>> </ul>
>>>
>>> Then allow the browser (maybe even OS specific) to assign standard key  
>>> shortcuts. In this way you get mouse-less browsing but with constancy  
>>> across applications and operating systems, and you don't have to be  
>>> prescriptive wrt browser manufacturers.
>>
>> There are a few things in basic HTML 4 that enable this. You won't get  
>> complete consistency - what I can do on a touch screen phone with 4  
>> buttons isn't the same as what I can do on a standard keyboard, and  
>> that is different from what i can do on a Russian keyboard. But a web  
>> application should be capable of adapting to all of these - and that  
>> means either a huge enomous and almost definitely hopelessly incomplete  
>> author-specified set of shortcuts, or a mechanism that allows the  
>> browser to assign the shortcut, with a default suggested by the author  
>> in the hope that it might be available.
>>
>>> Not sure if this helps any but I think we really need to look into  
>>> this.
>>
>> Agreed. Cheers
>>
>>> Cheers
>>> Si.
>>>
>>> =======================
>>>
>>> Simon Harper
>>> University of Manchester (UK)
>>>
>>> Human Centred Web Lab: http://hcw.cs.manchester.ac.uk
>>>
>>> My Site: http://hcw.cs.manchester.ac.uk/people/harper/
>>>
>>> My Diary (Web):  
>>> http://hcw.cs.manchester.ac.uk/people/harper/phpicalendar/week.php
>>> My Diary (Subscribe):  
>>> http://hcw.cs.manchester.ac.uk/diaries/harper/SimonHarper.ics
>>>
>>>
>>>
>>>
>>>
>>> On 31 Jul 2009, at 12:19, Henny Swan wrote:
>>>
>>>> Folks,
>>>>
>>>> Here's a copy of Chaal's mail to WAI-xtech concerning keyboard  
>>>> support and ARIA.
>>>>
>>>> Cheers, Henny
>>>>
>>>> Begin forwarded message:
>>>>
>>>>> Resent-From: wai-xtech@w3.org
>>>>> From: "Charles McCathieNevile" <chaals@opera.com>
>>>>> Date: 16 July 2009 16:37:01 BST
>>>>> To: "wai-xtech@w3.org" <wai-xtech@w3.org>
>>>>> Subject: Keyboard support and ARIA
>>>>>
>>>>> Hi folks,
>>>>>
>>>>> I have had a concern for a while (I recall raising it several times  
>>>>> over the last few years, but have been focussed on other things and  
>>>>> not followed so clearly) about the use of pure Javascript to deal  
>>>>> with keyboard accessibility.
>>>>>
>>>>> The major issue is the nature of keyboard interaction in Javascript.  
>>>>> Put briefly, it's a horrible mess with no concept of device  
>>>>> independence. So on the face of it, the idea that it would be a good  
>>>>> base for building accessibility seems like an odd notion.
>>>>>
>>>>> Digging into the details we find that several attempts to specify  
>>>>> this in a way considered workable have ended with clever people  
>>>>> throwing up their hands and saying "we could document some more of  
>>>>> the current mess, but it isn't actually anything you would want  
>>>>> people to use" (or things to that effect). Changing keyboard  
>>>>> layouts, browsers, devices, alphabets, language - almost anything  
>>>>> causes this to go from a nasty mess to a plain old failure.
>>>>>
>>>>> By comparison, the use of tabindex and real links or buttons, as per  
>>>>> old-fashioned HTML, seems to allow for a much more flexible  
>>>>> interaction model. HTML 5's command element, it's improved  
>>>>> specification of accesskey, and the growing understanding that this  
>>>>> stuff should be left to user agents and users rather than page  
>>>>> authors, offers the promise of being able to make keyboard  
>>>>> interaction actually work properly in more than one language or  
>>>>> device without having to develop massive collections of alternatives  
>>>>> with 5-variant testing to choose the right one.
>>>>>
>>>>> The migration path, as always, is actually messy. Currently  
>>>>> accesskey implementations range from not very good (e.g. Opera on  
>>>>> desktop which has some bugs and limitations, or really basic phone  
>>>>> browsers that only allow numbers) to the awful (e.g. things that let  
>>>>> pages override normal user agent interface), with a good dose of the  
>>>>> non-existent. Meanwhile, interrupting everything with javascript  
>>>>> means that the issue of where the priority should go is also raised.
>>>>>
>>>>> I don't think these are insoluble problems, but I do see a lot of  
>>>>> work moving in a direction that looks like a very ugly ad very  
>>>>> limiting dead-end, that could actually significantly reduce the  
>>>>> practical value of ARIA far below its potential.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Chaals
>>>>>
>>>>> --Charles McCathieNevile  Opera Software, Standards Group
>>>>>    je parle français -- hablo español -- jeg lærer norsk
>>>>> http://my.opera.com/chaals       Try Opera: http://www.opera.com
>>>>
>>>>
>>>>
>>>>
>>>> --Henny Swan
>>>> Web Evangelist
>>>> Member of W3C Web Accessibility Initiative Education and Outreach  
>>>> Group
>>>> www.opera.com/developer
>>>>
>>>> Personal blog: www.iheni.com
>>>>
>>>> Stay up to date with the Web Standards Curriculum www.opera.com/wsc
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>>
>> --Charles McCathieNevile  Opera Software, Standards Group
>>     je parle français -- hablo español -- jeg lærer norsk
>> http://my.opera.com/chaals       Try Opera: http://www.opera.com
>>
>


-- 
Charles McCathieNevile  Opera Software, Standards Group
     je parle français -- hablo español -- jeg lærer norsk
http://my.opera.com/chaals       Try Opera: http://www.opera.com
Received on Saturday, 1 August 2009 14:41:11 GMT

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