E-mail List Archives
Thread: Accessible captchas?
Number of posts in this thread: 15 (In chronological order)
From: Dean Hamack
Date: Wed, Dec 03 2008 12:50PM
Subject: Accessible captchas?
No previous message | Next message →
I'm putting together a contact form and need to have a captcha to prevent
spam. Does anyone have recommendations for an accessible method? First hit
in Google turned up this:
http://www.purple-dogfish.co.uk/free-stuff/accessible-captcha
From: Peter Krantz
Date: Wed, Dec 03 2008 1:05PM
Subject: Re: Accessible captchas?
← Previous message | Next message →
On Wed, Dec 3, 2008 at 8:47 PM, Dean Hamack < = EMAIL ADDRESS REMOVED = > wrote:
> I'm putting together a contact form and need to have a captcha to prevent
> spam. Does anyone have recommendations for an accessible method? First hit
> in Google turned up this:
>
> http://www.purple-dogfish.co.uk/free-stuff/accessible-captcha
>
Briefly looking through the examples at the link you provided makes
one wonder about the accessibility. Metaphors and math may be
difficult for people with cognitive disabilities.
Are you sure you need a captcha? Is it possible to instead use a
server-side service (like Akismet) to deal with spam?
Regards,
Peter Krantz
From: Jared Smith
Date: Wed, Dec 03 2008 1:15PM
Subject: Re: Accessible captchas?
← Previous message | Next message →
On Wed, Dec 3, 2008 at 1:04 PM, Peter Krantz < = EMAIL ADDRESS REMOVED = > wrote:
> Are you sure you need a captcha? Is it possible to instead use a
> server-side service (like Akismet) to deal with spam?
Of maybe some of the approaches I outlined here -
http://www.webaim.org/blog/spam_free_accessible_forms/
Stopping spam is a pretty marginal reason for burdening all of your
users with a CAPTCHA. Implementing just a few of these techniques will
stop 99%+ of spam without affecting the usability of the page at all.
Those human spammers still get through, but CAPTCHA won't stop them
either.
Jared Smith
WebAIM
From: Dean Hamack
Date: Wed, Dec 03 2008 1:25PM
Subject: Re: Accessible captchas?
← Previous message | Next message →
That's kind of what I figured. I don't think Akismet will work for a contact
form (although I'm not positive).
This method I found seems to be a good alternative:
http://checkengineusa.com/dennislembree/blog/2007/07/16/how-to-use-free-capt
chasnet-and-stop-spam/
On 12/3/08 12:04 PM, "Peter Krantz" < = EMAIL ADDRESS REMOVED = > wrote:
> Briefly looking through the examples at the link you provided makes
> one wonder about the accessibility. Metaphors and math may be
> difficult for people with cognitive disabilities.
>
> Are you sure you need a captcha? Is it possible to instead use a
> server-side service (like Akismet) to deal with spam?
>
> Regards,
>
> Peter Krantz
>
From: Dean Hamack
Date: Wed, Dec 03 2008 1:35PM
Subject: Re: Accessible captchas?
← Previous message | Next message →
Good tips. Thanks Jared.
On 12/3/08 12:14 PM, "Jared Smith" < = EMAIL ADDRESS REMOVED = > wrote:
> Of maybe some of the approaches I outlined here -
> http://www.webaim.org/blog/spam_free_accessible_forms/
>
> Stopping spam is a pretty marginal reason for burdening all of your
> users with a CAPTCHA. Implementing just a few of these techniques will
> stop 99%+ of spam without affecting the usability of the page at all.
> Those human spammers still get through, but CAPTCHA won't stop them
> either.
>
> Jared Smith
> WebAIM
From: Suki Beg
Date: Thu, Dec 04 2008 3:20AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
I've been investigating www.captcha.net recently, which features a sound
file with generated captcha graphics, howeverI wonder if these may be
confusing for non-English speakers.
Suki Beg
GLE Group Web Developer
GLE
T: 020 7940 1549
New City Court
20 St Thomas Street
London SE1 9RS
www.gle.co.uk
The contents of this email and any attachments are confidential to the
intended recipient. They may not be disclosed to, used by or copied in
any way by anyone other than the intended recipient. Whilst any
information and/or any opinion given is believed to be correct, it is
not intended to constitute legal advice; you should seek specific legal
advice as appropriate. Please note that GLE does not accept any
responsibility for viruses and it is your responsibility to scan or
otherwise check this email and any attachments.
Please only print this email if absolutely necessary
Registered office: New City Court, 20 St Thomas Street, London SE1 9RS
Registered number: 1653116 VAT number: 237 9198 23
From: Stephan Wehner
Date: Thu, Dec 04 2008 8:25AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
On Wed, Dec 3, 2008 at 12:14 PM, Jared Smith < = EMAIL ADDRESS REMOVED = > wrote:
> On Wed, Dec 3, 2008 at 1:04 PM, Peter Krantz < = EMAIL ADDRESS REMOVED = > wrote:
>> Are you sure you need a captcha? Is it possible to instead use a
>> server-side service (like Akismet) to deal with spam?
>
> Of maybe some of the approaches I outlined here -
> http://www.webaim.org/blog/spam_free_accessible_forms/
Those suggestions seem to be suitable against a generic
form-spam-robot "one-size-fits-all".
However, the approaches look pretty easy to overcome on a site-by-site basis:
Quoting from http://www.webaim.org/blog/spam_free_accessible_forms
"The techniques are:
* Detect spam-like content within submitted form elements
* Detect content within a hidden form element
* Validate the submitted form values
* Search for the same content in multiple form elements
* Generate dynamic content to ensure the form is submitted within
a specific time window or by the same user
* Create a multi-stage form or form verification page
* Ensure the form is posted from your server"
Stephan
> Stopping spam is a pretty marginal reason for burdening all of your
> users with a CAPTCHA. Implementing just a few of these techniques will
> stop 99%+ of spam without affecting the usability of the page at all.
> Those human spammers still get through, but CAPTCHA won't stop them
> either.
>
> Jared Smith
> WebAIM
>
From: Randall Pope
Date: Thu, Dec 04 2008 8:50AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
Using this caphchas approach, would not be accessible for the deaf-blind
audience. Many cannot hear the voice.
Randy
American Association of the Deaf-Blind
From: Suki Beg
Date: Thu, Dec 04 2008 8:55AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
Would a screen reader be able to read this kind of captcha -
http://www.purple-dogfish.co.uk/free-stuff/accessible-captcha?
From: Randall Pope
Date: Thu, Dec 04 2008 9:10AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
Assuming that the purpose is to keep spam bots from accessing the website,
this may work for the DeafBlind people. As long it is not voice or graphic
only, we the Deafblind people will be happy. Smile.
Randy
From: Dean Hamack
Date: Thu, Dec 04 2008 11:30AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
This is very helpful information, thanks.
Forgive my ignorance, as I am new to the accessibility field. How do people
who are both deaf and blind access information on web pages. Is there some
kind of device that translates the content to braille?
On 12/4/08 8:10 AM, "Randall Pope" < = EMAIL ADDRESS REMOVED = > wrote:
> Assuming that the purpose is to keep spam bots from accessing the website,
> this may work for the DeafBlind people. As long it is not voice or graphic
> only, we the Deafblind people will be happy. Smile.
>
> Randy
From: Moore, Michael
Date: Thu, Dec 04 2008 11:40AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
<HTML dir=ltr><HEAD><TITLE>Re: [WebAIM] Accessible captchas?</TITLE>
<META http-equiv=Content-Type content="text/html; charset=unicode">
<META content="MSHTML 6.00.6000.16735" name=GENERATOR></HEAD>
<BODY>
<DIV id=idOWAReplyText84152 dir=ltr>
<DIV dir=ltr><FONT face=Arial color=#000000 size=2>JAWS and Window Eyes will both provide output to a refreshable braille display. Audio alternative captcha's obviously will not work for this audience. I recommend reducing spam using the methods outlined on WebAIM's site. The direct link was posted by Jared yesterday.</FONT></DIV>
<DIV dir=ltr><FONT face=Arial size=2></FONT> </DIV>
<DIV dir=ltr><FONT face=Arial size=2>Mike</FONT></DIV></DIV>
<DIV dir=ltr><BR>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> = EMAIL ADDRESS REMOVED = on behalf of Dean Hamack<BR><B>Sent:</B> Thu 12/4/2008 12:27 PM<BR><B>To:</B> WebAIM Discussion List<BR><B>Subject:</B> Re: [WebAIM] Accessible captchas?<BR></FONT><BR></DIV>
<DIV>
<P><FONT size=2>This is very helpful information, thanks.<BR><BR>Forgive my ignorance, as I am new to the accessibility field. How do people<BR>who are both deaf and blind access information on web pages. Is there some<BR>kind of device that translates the content to braille?<BR><BR><BR>On 12/4/08 8:10 AM, "Randall Pope" < = EMAIL ADDRESS REMOVED = > wrote:<BR><BR>> Assuming that the purpose is to keep spam bots from accessing the website,<BR>> this may work for the DeafBlind people. As long it is not voice or graphic<BR>> only, we the Deafblind people will be happy. Smile.<BR>><BR>> Randy<BR><BR><BR>
From: Dean Hamack
Date: Thu, Dec 04 2008 11:50AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
I only briefly skimmed the Jared's article, but if I understand it
correctly, it said one of the methods was to look for urls in the form
fields and mark the message as spam if it finds them. That's a big problem
for web developers since a lot of the messages I get from potential clients
are like this:
"How much would you charge me to build a site that looks like
www.example.com?"
If all those messages get flagged as spam, I lose a lot of business.
In looking at all of the options, I think the best option may be to have a
very simple captcha question like "what color is the sky?"
On 12/4/08 7:20 AM, "Stephan Wehner" < = EMAIL ADDRESS REMOVED = > wrote:
> "The techniques are:
> * Detect spam-like content within submitted form elements
From: Moore, Michael
Date: Thu, Dec 04 2008 11:55AM
Subject: Re: Accessible captchas?
← Previous message | Next message →
Obviously you have to choose methods that will work within your own constraints, if you are expecting URLs in a field then you would not flag them as spam. The simple question challenge that you mentioned is a good alternative and will not likely pose a barrier for many, if any real customers. I always provide multiple methods for contact with potential customers on sites that I design, and include postal addresses and telephone contact info to supplement the web contact/form/email info.
Mike
From: Owens, Parker
Date: Fri, Dec 05 2008 10:15AM
Subject: Re: Accessible captchas?
← Previous message | No next message
Here's some additional stuff from WCAG 2:
If CAPTCHAs are used:
Provide more than two modalities of CAPTCHAs
Provide access to a human customer service representative who can bypass CAPTCHA
Do not require CAPTCHAs for authorized users
I think the second one is the most important.
Parker Owens
Web Accessibility Office
Eastern Kentucky University
254 Case Annex
Richmond, KY 40475
Phone: (859) 622-2743
http://www.accessibility.eku.edu