[whatwg] [HTML5] Accessibility question

Nicholas Shanks contact at nickshanks.com
Tue Apr 1 03:07:13 PDT 2008


On 1 Apr 2008, at 10:14 am, Benjamin Hawkes-Lewis wrote:

> Nicholas Shanks wrote:

>> I know that everyone already knows this, but I think a reminder  
>> might be timely:
>> Be careful not to confuse screen readers, who's job it is to read  
>> what is displayed on the screen,
>
> That's something of a simplification; the word "read" in particular  
> is as likely to confuse as to clarify (yes, the name doesn't help  
> here). It's the job of a screen reader to provide people with severe  
> visual impairments with access to a computer system.

Well i would disagree: that's the job of an accessibility suite for  
the blind. A screen reader is just one component of such a suite.

> That regularly entails more than "reading what is displayed on  
> screen", including also things like querying document or application  
> models and constructing further internal models on top of those (for  
> example, to produce a list of links, or extract hidden help text, or  
> construct a text-stream view of a webpage in a virtual buffer).

> http://www.rnib.org.uk/xpedio/groups/public/documents/PublicWebsite/public_withoutvisinfosheet.hcsp
> http://en.wikipedia.org/wiki/Screen_reader
>
> "A program whose 'job it is to read what is displayed on the screen'  
> " works better as a description of simpler text-to-speech programs  
> (which also exist).

Am at work and haven't time to read these at the moment. Will do so  
this evening.

>> with a voice browser, who's job it is to parse a HTML document into  
>> a DOM tree and apply media-less and aural CSS (and potentially  
>> never display anything on screen).
>
> I agree it's important to distinguish screen readers from voice  
> browsers. Two example differences from an end-user perspective:
>
> 1. Screen readers typically provide access to an entire system  
> rather than simply being a self-voicing application for browsing the  
> web or an application that happens to include speech output.
>
> 2. Screen readers also typically output braille. :)

Then I would call such software a "screen reader + braille renderer +  
hacks around in your OS program doing nasty things" program. I don't  
think a pure screen reader should know anything about CSS or DOM or an  
application's internals.

>> visibility: hidden and display: none should both hide content from  
>> screen readers.
>
> I don't think it's that clear-cut in theory or practice. Screen  
> readers don't map directly to the speech/aural or braille media  
> types. But they don't map directly to the screen media type either.  
> They involve different modes of access, not just a different media  
> type.
>
> See also one slice of the complicated story at:
>
> "Does JAWS support cascading style sheets (CSS)?"
> http://www.freedomscientific.com/fs_support/BulletinView.cfm?QC=1165

Besides my opinion that JAWS is probably the worst example of an  
accessibility program that exists, it is far from being just a screen  
reader.


— Nicholas Shanks.

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