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Web Site and Web Application Accessibility with Orca and Firefox

The free software community is at the forefront of efforts to make the World
Wide Web more accessible to people with disabilities. In this presentation I
shall discuss, and demonstrate, the use of Mozilla Firefox 3 with the Orca
screen reader, with which it is now possible to make Web sites and Web
applications available through braille and speech-based interaction in a Linux

The underlying theme of the presentation is the concept of an accessibility
API. After a brief historical introduction, I shall outline the architecture
of Orca and of the Gnome accessibility infrastructure (ATK and AT-SPI),
explaining how these components interact to enable non-visual access to the
Web. The structural navigation features of Orca, written specifically for
Firefox, are described, emphasizing the extent to which the usability of the
braille or speech-based interface depends on the fidelity with which the
structure of the underlying Web content is marked up explicitly in the HTML

Web sites and interactive applications that rely on client-side Javascript to
construct dynamic user interfaces, and to create user interface elements that
cannot be obtained via HTML forms, have posed insuperable obstacles to users
of screen readers. Having explained and illustrated this problem, I shall
introduce Aria, the Accessible Rich Internet Applications specification of the
W3C, first implemented in Firefox, which extends the concept of an
accessibility API beyond the desktop by integrating it into Web applications
and client-side Javascript libraries. This is achieved by defining a standard
set of Aria attributes, to be embedded in host languages such as HTML and
XHTML, for declaratively characterizing custom user interface controls, as
well as commonly occurring Web document structures that are poorly addressed
in the host language itself.

After describing some useful Firefox extensions that further enhance the
accessibility of Web sites and interactive Web-based user interfaces, notably
Google-Axsjax, the presentation concludes with an overview of related
development efforts, such as the implementation of support for screen readers
and Aria in the GTK+ port of WebKit.

Jason White

Jason has been enthusiastically using GNU/Linux since 1998, with both braille
and speech output. Following technical collaboration with Dave Mielke, the
maintainer of BRLTTY, in which a driver was extended to support his braille
display device, Jason finally shelved his old DOS machine and was able to use
GNU/Linux exclusively.

Jason is an active participant in project mailing lists devoted to free
software and accessibility. He has also participated in beta testing and
helped to track down bugs in a number of projects, most recently the
combination of Firefox 3 and the Orca screen reader, which he uses to access
Web sites that rely on client-side Javascript.

Since the mid 1990's, Jason has been extensively involved in technical
standard-setting activities related to accessibility for people with
disabilities. From 2000 to 2004 he served as co-Chair of the Web Content
Accessibility Guidelines working group of the World Wide Web Consortium (W3C).
He has also participated in working groups that have enhanced the support for
accessibility provided by a number of W3C technical specifications, such as
HTML, CSS and SVG. Since 1998, he has contributed to technical committees of
the Daisy Consortium, developing standards and DTD's for accessible electronic

In real life, Jason is a Ph.D. student in philosophy, devoting much of his
time to writing about conceptual issues in contemporary analytic semantics.