[Athen] Accessible CAPCTCHA

Terry Thompson tft at u.washington.edu
Thu Feb 8 08:17:31 PST 2007

Hi Larry,

I've seen a couple of strategies for making captchas accessible:

1. Provide an audio version for those who can't see the captcha image. I've
done this myself on several websites using Ed Eliot's Visual and Audio PHP
CAPTCHA class:


2. Provide some sort of question or problem that can be easily answered by
humans, but not-so-easily answered by computers. Here's an example of this
approach from the University of Wisconsin - Madison:


Neither of these is perfect. The first approach offers no solution for folks
who are deaf-blind. And the second approach may present challenges for those
with cognitive disabilities who can't answer the question. In the case of
the Wisconsin solution, the user must be able to perform simple mathematical
calculations, which some users may have difficulty with.

The W3C has written a more detailed "working group note" on this topic:


Terry Thompson
Technology Specialist, DO-IT
University of Washington
tft at u.washington.edu


From: athen-bounces at athenpro.org [mailto:athen-bounces at athenpro.org]
On Behalf Of Larry Kiser
Sent: Thursday, February 08, 2007 8:00 AM
To: athen at athenpro.org
Subject: [Athen] Accessible CAPCTCHA

Dear Colleagues:

I am submitting the following question at the request of my
coordinator. How can you get the functionality of a captcha and still be
508 compliant? Our institution is considering the use of captchas (heaven
only know why) on some web pages. I look forward to your responses.

Larry Kiser

Santa Fe Community College

Disabilities Resource Center

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