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Re: Generated CSS content and browser/assistive technology compatibility

From: Matthew King <mattking@us.ibm.com>
Date: Fri, 10 Oct 2014 01:06:33 -0700
To: Marco Zehe <mzehe@mozilla.com>
Cc: Dominic Mazzoni <dmazzoni@google.com>, James Nurthen <james.nurthen@oracle.com>, W3C WAI Protocols & Formats <public-pfwg@w3.org>
Message-ID: <OF1B128F22.42B6651A-ON88257D6D.002B5C1C-88257D6D.002C8C17@us.ibm.com>
Marco, that was true in the past, but I know it is no longer the case. 
JAWS relies heavily on the DOM in IE, but has moved away from the DOM 
toward IA2 in Firefox.
When this thread revealed to me that the FF a11y tree had the generated 
content, I started a conversation with Freedom Scientific.
JAWS is revealing generated content in some cases, but not others. I am 
curious to learn what the root cause of the defect is.

For example, JAWS works on the example at:
http://www.w3schools.com/cssref/sel_before.asp

But not on the W3C doc at:
http://www.w3.org/TR/css3-flexbox/

Matt King
IBM Senior Technical Staff Member
I/T Chief Accessibility Strategist
IBM BT/CIO - Global Workforce and Web Process Enablement 
Phone: (503) 578-2329, Tie line: 731-7398
mattking@us.ibm.com



From:   Marco Zehe <mzehe@mozilla.com>
To:     James Nurthen <james.nurthen@oracle.com>, Dominic Mazzoni 
<dmazzoni@google.com>, 
Cc:     W3C WAI Protocols & Formats <public-pfwg@w3.org>
Date:   10/10/2014 12:03 AM
Subject:        Re: Generated CSS content and browser/assistive technology 
compatibility



That is correct, JAWS is doing its own HTML parsing, like in IE, and is 
not using the info from the accessibility tree. Neither is Window-Eyes if 
that still has any relevance.

Frustrating, I know, but from our end, there's nothing we could do except 
cut all support for ISimpleDOM, but that would leave all JAWS users in the 
dark for an indeterminable amount of time. ;)

Marco

On 09.10.2014 20:13, James Nurthen wrote:
I note that FF is exposing it in the accessibility tree too.

I guess JAWS isn't using the accessibility tree for text as JAWS won't 
read it with FF.

Regards,
James

On 10/9/2014 11:05 AM, Dominic Mazzoni wrote:
Works fine in Chrome too, presumably with any assistive technology since 
we're exposing the generated content in the accessibility tree. 

On Thu, Oct 9, 2014 at 10:58 AM, James Nurthen <james.nurthen@oracle.com> 
wrote:
I just tested with NVDA and Firefox 31 and it seemed to be read correctly 
in this combination too. 



On 10/9/2014 10:51 AM, Gunderson, Jon R wrote:
James,

Thank you for the code sample.

At this point the only known place generated CSS content works with 
assistive technology is Safari/Voice Over or are there other combinations 
you are aware of?

Jon


-----Original Message-----
From: James Craig [mailto:jcraig@apple.com] 
Sent: Thursday, October 09, 2014 12:28 PM
To: Gunderson, Jon R
Cc: Ted O'Connor; W3C WAI Protocols & Formats
Subject: Re: CSS flexbox


On Oct 9, 2014, at 6:34 AM, Gunderson, Jon R <jongund@illinois.edu> wrote:

Is there a way through a W3C DOM interface to identify this generated 
content?

CSSOM not DOM:
var pseudoBefore = window.getComputedStyle(myElement, "::before"); var 
genContent = pseudoBefore.getPropertyValue("alt") || 
pseudoBefore.getPropertyValue("-webkit-alt") || 
pseudoBefore.getPropertyValue("content");

If "content" returned an image URL string, you'd have to further parse to 
determine if there was a useful text alternative, or maybe the text or 
speak-as value of the counter if the content of the pseudo-element was a 
counter. [1]

>From the spec:

If pseudoElt is as an ASCII case-insensitive match for either ':before' or 
'::before' let obj be the ::before pseudo-element of elt.
If pseudoElt is as an ASCII case-insensitive match for either ':after' or 
'::after' let obj be the ::after pseudo-element of elt.

http://dev.w3.org/csswg/cssom/#dom-window-getcomputedstyle
http://dev.w3.org/csswg/cssom/#dom-cssstyledeclaration-getpropertyvalue

Cheers,
James

1. 
http://lists.w3.org/Archives/Public/www-style/2014May/thread.html#msg146





-- 
Regards, James 

James Nurthen | Principal Engineer, Accessibility
Phone: +1 650 506 6781 | Mobile: +1 415 987 1918 
Oracle Corporate Architecture
500 Oracle Parkway | Redwood City, CA 94065 
Oracle is committed to developing practices and products that help protect 
the environment 


-- 
Regards, James 

James Nurthen | Principal Engineer, Accessibility
Phone: +1 650 506 6781 | Mobile: +1 415 987 1918 
Oracle Corporate Architecture
500 Oracle Parkway | Redwood City, CA 94065 
Oracle is committed to developing practices and products that help protect 
the environment 


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Received on Friday, 10 October 2014 08:07:08 UTC

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