[Athen] Accessibility of standards-based slide tools (was: Accessible Office Export Plug-In That's NOT UIUC)

[Terry Thompson]

> Turning off the CSS in the browser seems to improve the presentation 

> navigation with JAWS tremendously...which raises a very 

> interesting question as to why does CSS have so much control 

> over how JAWS functions?!?.


It's actually not CSS that's the problem with S5 and similar tools such as
W3C Slidy - it's Javascript. Each of these tools is similar in that they
take a single HTML file, then intermittently hide and reveal portions of it
in order to create the slideshow effect. This hiding and revealing is
accomplished in part using CSS - but the real behind-the-scenes magic is
performed by Javascript. The problem for screen reader users is that
Javascript is intercepting keystrokes and interpreting them to be S5 or
Slidy commands, whereas the user might have intended those keystrokes to be
handled by their screen reader. 

The variance in behavior across versions and browsers is what really
interests me though. Using the latest versions of everything (JAWS 8,
Internet Explorer 7, and Firefox 2) the precedence of which application is
first in the keystroke chain seems to go like this on a web page that
contains an S5 presentation:  

1. Browser
2. Screen reader 
3. Web page/Javascript (S5)

In this scenario, screen readers read the presentation pretty well, but the
S5 navigation is broken. 
For example, users are supposed to be able to advance slides with Space bar,
Return, Right arrow, Down arrow, and Page down, but if either the browser or
the screen reader uses these keystrokes for other purposes these keys don't
work to advance the slides. As Sean mentioned, Alt + right arrow seems to be
a workaround, but that's only true if the forward button in the browser is
unavailable. Otherwise Alt + right arrow would be used by the browser as a
hotkey for the "forward button". Even if Alt + right arrow works to advance
the slide, one might intuitively expect Alt + left arrow to move to the
preceding slide, but this is subject to the same restrictions - it won't
work unless the slideshow is the first web page opened in the current
browser window. Otherwise it will activate the browser's back button. 

The broken S5 functionality actually doesn't matter for Window-Eyes users
(using version 6 anyway - I haven't tried earlier versions). Window-Eyes
simply ignores CSS and reads everything whether it's hidden or not. I don't
think we can really fault other screen readers for hiding invisible content
though - that would seem to be a design philosophy rather than a bug. (If
something is hidden from sighted users, shouldn't it be hidden from blind
users too?) 

Interestingly, W3C Slidy, which is a very similar product to S5, does not
seem to have the same order of precedence for interpreting keystrokes: 

1. Browser
2. Web page/Javascript (Slidy)
3. Screen reader

This is a much worse scenario for screen reader users, as when they press
common screen reader keys like the down arrow, Slidy advances the slides but
the screen reader doesn't read anything. This means that even Window-Eyes
users are shut out of W3C Slidy presentations. 

So, an important question this raises is: What's the difference in these two
products? If we agree that keystrokes should be passed through assistive
technology before being handled by a web page's Javascript, how has Eric
Meyer accomplished this with S5? I don't think Eric subscribes to this list
so I'll ask him under separate cover and keep you posted. If this is a
Javascript technique issue as it seems to be, it will be good for us to
document as a best practice and spread the word. I'm sure this isn't the
last keyboard-enabled web application we'll be seeing. 

Terry 



> -----Original Message-----

> From: athen-bounces at athenpro.org 

> [mailto:athen-bounces at athenpro.org] On Behalf Of Sean Keegan

> Sent: Monday, February 12, 2007 3:01 PM

> To: 'Access Technologists in Higher Education Network'

> Subject: Re: [Athen] Accessible Office Export Plug-In That's NOT UIUC

> 

> > While S5 is great way to create a presentation on the web it is not 

> > really accessible with Jaws as all the keystrokes needed to 

> move the 

> > presentation forward are defined by Jaws to perform dfferent 

> > functions.

> 

> I think this raises an interesting question as to assistive 

> technology support  of Web standards.  Is the S5 Web 

> presentation model accessible using JAWS?  Sure - but it 

> really depends on what version of JAWS you are using AND what 

> Internet browser.  A presentation with the S5 system could be 

> accessed with JAWS 7.x and Firefox, but not Internet Explorer 

> (JAWS 8 has improvements with IE and the S5 system).  Turning 

> off the CSS in the browser seems to improve the presentation 

> navigation with JAWS tremendously...which raises a very 

> interesting question as to why does CSS have so much control 

> over how JAWS functions?!?.

> 

> Side note: For using a screen-reader with S5 - to move one 

> screen ahead, press Alt + Right Arrow.

> 

> Here is my issue though: the S5 system is a standards-based 

> implementation of XHTML, CSS, and Javascript.  I would argue 

> that the developers of such AT need to recognize that better 

> support of Web standards is a necessity and the lack of 

> access is not so much a problem of the presentational system 

> (i.e., S5), but rather poor implementation of the Web feature 

> set by the AT vendor.

> 

> Granted, there is still an issue of limited access by the 

> individual and that is why I generally advocate the idea of 

> posting multiple formats of the presentation - let site 

> visitors choose the file-type they like the most.

> However, I do believe that better implementations of 

> standards-compliant (or perhaps standards-supportive) 

> assistive technology is a necessity as we move forward in 

> implementing new models of communication.

> 

> 

> Take care,

> Sean

> 

> 

> -----Original Message-----

> From: athen-bounces at athenpro.org 

> [mailto:athen-bounces at athenpro.org] On Behalf Of Saroj Primlani

> Sent: Saturday, February 10, 2007 12:30 PM

> To: athen at athenpro.org

> Subject: Re: [Athen] Athen Digest, Vol 13, Issue 11

> 

> While S5 is great way to create a presentation on the web it 

> is not really accessible with Jaws as all the keystrokes 

> needed to move the presentation forward are defined by Jaws 

> to perform dfferent functions.  I learnt that the hard way Saroj

> 

> 

> 

> _______________________________________________

> Athen mailing list

> Athen at athenpro.org

> http://athenpro.org/mailman/listinfo/athen_athenpro.org

>