Exception #0815 in function "subtitle_generator", Error: Visitor IQ too low!

WP-Plugin: dennis2society Advanced Math Captcha

2008/03/01 – 01:20


Description: WordPress-Plugin to prevent comment spam

In contradiction to conventional CAPTCHA systems this solution does not simply require to recognize distorted numbers or letters or maybe solve an addition or subtraction, but instead challenges the user ( or spambot ) to solve REAL mathematical equations such as derivation or a limit ( limes ) .

Captcha-Sample 2This is admittedly not totally barrier-free but will at least handicap the common spam bot. And people who don’t know about mathematics…

The challenge-list will be extended in the future. Hopefully. Further suggestions and submissions are explicitly welcome. The only constraint is that the solution has to consist of max. two ( 2 ) digits/letters with no special characters in it .

Installation: Download and unpack the archive. Copy the entire folder to your WordPress plugin directory.


  • Find more challenges.
  • Translate some challenges from German to English ( what’s the English word for ‘Nullstelle’? )
  • Rename the current captcha image and copy it to a new folder as currently the solution can be guessed by evaluating the file name.

Demo: see below…. ( when not logged in )

Download: Download

Post a Comment

Insert a smiley:

To prevent spam and comments of people who don't
know about mathmatics you have to enter the result
into the field on the right side.
Hint: Possible answers are '-3', '-2', '0', '1' and '6x'.
Some challenges have more than one correct answer!
Spam protection