I've not tried this captcha yet but as it is based in CSS then is it not going to work for those who override site CSS for various reasons. As an example suppose a person uses firefox and sets their own styles (user.css) as they are vision impaired/partially sighted.
I always worry about putting too much logic/content into CSS for this reason. If the colours are in the CSS as opposed to a gif/image then some will override this and not be able to use the captcha.
Alexander Selifonov - 2008-05-07 16:24:40 - In reply to message 1 from Jason Bailey
If You cannot trust CSS (one of the most useful technics today, i think), so what can You do with Your site design and PHP code ?
Get back to the obsolete bgcolor=.. coding ? Or inject "style=" in every HTML tag ? I'm not sure that it's a good idea. CSS is one of the best ways to separate program code from design/formatting/color schemes.
I didn't know about such a useful feature in Firefox like CSS substitutions/overrides, but I believe that if somebody use it, He should take all responsibility for this.
Anyway, if someone really worries about css overrides, it's not a problem to add PHP code for generating "inplace" CSS styles with random names, so there will be no chance to "guess" them in the user.css. If this issue really occures someday, I'll add this code into my class.