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Re: Browser detection and screen readers

for

From: Jared Smith
Date: Aug 1, 2003 10:25AM

Because many screen readers are supplements to existing Web browsers
(typically Internet Explorer), you really cannot detect the existence
of a screen reader on the server side, as the header requests indicate
that it is really a standard Web browser. And I agree with Karl -
detecting a screen reader to present different content does little for
true accessibility.

The only way I know of to detect the presence of a screen reader is to
use Flash to detect if the browser is monitoring for MSAA (Microsoft
Active Accessibility) events. This will only work with newer versions
of screen readers on Windows - to date, Jaws 4.5+ and Window Eyes
4.21+. And, the user must have the Flash player 6+ installed. Again,
such an approach is very limiting, yet possible. You can detect the
screen reader and redirect accordingly by adding

if (Accessibility.isActive()) {
getURL(screenreaderpage.htm);
} else {
getURL(normalpage.htm);
}

to a keyframe in your Flash movie.

Jared Smith
WebAIM (Web Accessibility In Mind)
Center for Persons with Disabilities
Utah State University



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On Friday, August 01, 2003 you sent:
c> Hi
c> has anyone done server-side browser detection to detect a screen reader and
c> serve up an appropriate page layout (i.e. alternative css sheet)?

c> If so, is there a User Agent list somewhere that I'm just not finding?

c> Thanks
c> -chris


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