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Re: Action-650 Review generated css content in html5

From: Jim Allan <jimallan@tsbvi.edu>
Date: Thu, 15 Dec 2011 16:52:07 -0600
Message-ID: <CA+=z1WmKVU7JPapt1bYqbKznuch1Hfaxcf3XpZ4nTzT-RiGk0w@mail.gmail.com>
To: WAI-ua <w3c-wai-ua@w3.org>, Charles McCathieNevile <chaals@opera.com>
After some though and testing...I am not finished with this topic.

Generated Content is content generated by CSS that appears in the UA
viewport. The content is placed in CSS by the author.

Generated content may be an image. There is no facility in CSS to
generate alternative content for images in CSS. There are image
replacement techniques for this case that allow html text to be read
by assistive technology. The author must create these.

Generated content may contain text (alpha-numeric). This content does
not appear in the HTML DOM.  It may appear in the CSS Object Model.

I think the underlying Accessibility principle is if text (from
whatever source, apart from images) appears in the user agent's
viewport it should be accessible to screenreaders, screen magnifiers,
copy, print, and search. As it appears in the viewport it is up to the
user agent to make the text available to the appropriate mechanisms to
ensure the accessibility.

Testing so far (need some help for Mac browsers and Unix/Linux browsers)

1. Printing - prints on Windows (FF, IE, Chrome, Opera), Mac ? others?
2. Select/copy - No access (mouse or keyboard can't touch it) on
Windows (FF, IE, Chrome, Opera), Mac ? others?,
3. Search - Search on Windows works in Opera (it moves the searched
for word into the viewport, but does not highlight the word), does not
work on FF, IE, Chrome. Mac ?, others?
4. Screenreader access - Windows - yes Chrome.  No - FF, IE, Opera.
Mac - yes Opera, Safari. others not tested.

In UAAG 2.4.1 Find: The user can perform a search within rendered
content (e.g. not hidden with a style), including text alternatives,
for any sequence of characters from the document character set. (Level
A)

I think we should add generated content to this success criteria.
Other success criteria related to search 2.4.2 - 5 build on 2.4.1 so
generated content will not have to be repeated.

something like
2.4.1 Find: The user can perform a search within rendered or generated
content (e.g. not hidden with a style), including text alternatives,
for any sequence of characters from the document character set. (Level
A)

Could we construe rendered content to include content generated by
CSS?. Is the content generated from CSS still sent to the UA rendering
engine, so could be considered rendered content? I don't know. Does
any one have an answer.

Perhaps we need a success criteria in Principle 1 Perceivable.
1.1.x Rendered Text: If text appears visually in the view port the
user can do the following:
* select the text (for copy operations)
* search for the text
* print the text
* have the text exposed to the accessibility API.

Thoughts?

Jim


On Wed, Nov 9, 2011 at 11:09 AM, Jim Allan <jimallan@tsbvi.edu> wrote:
> could find no reference to prohibiting CSS generated content from appearing
> in the DOM.
> there doesn't appear to be anything that a UA can do to access this
> information. A screen reader could scrape the screen and keep refreshing to
> find generated content...tedious, many cpu cycles, etc.
> generated content fails WCAG20 - generated content does not work
> http://cssgallery.info/testing-the-accessibility-of-the-css-generated-content/
>
> I will give up any issues I had about this.
> Recommend closing this Action.
>
> --
> Jim Allan, Accessibility Coordinator & Webmaster
> Texas School for the Blind and Visually Impaired
> 1100 W. 45th St., Austin, Texas 78756
> voice 512.206.9315    fax: 512.206.9264  http://www.tsbvi.edu/
> "We shape our tools and thereafter our tools shape us." McLuhan, 1964



-- 
Jim Allan, Accessibility Coordinator & Webmaster
Texas School for the Blind and Visually Impaired
1100 W. 45th St., Austin, Texas 78756
voice 512.206.9315    fax: 512.206.9264  http://www.tsbvi.edu/
"We shape our tools and thereafter our tools shape us." McLuhan, 1964
Received on Thursday, 15 December 2011 22:58:29 GMT

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