How to add captcha?

I get lot of spam emails through my contact form, so is there anyway where i can add captcha ( image verification ) to stop the bots
if so where can i get that script ??

Thanx

 

You can use php class for that at http://www.phpclasses.org/

 

Thanx lemme see if it helps
Sorry it didnt worked

 

I use this one - http://www.puremango.co.uk/cm_php_captcha_script_113.php

hope it helps,
stuart

 

When i tried to install PhpLD it was showing me that GDlib has not been installed.
Now what should i do for that??

 

well a captcha image is probably out. Maybe some sort of logic challenge? Set up a question which asks for a certain result such as 'what is 3 + 5?' You would need the numbers to be dynamic and change though.

 

How about a JavaScript captcha? If bots can't read images, they can't run javascript. So, generate a number with php, store it in a session, let javascript write it and then check it in the other page.

 

And what if the user has Javascript disabled? He won't be able to use the contact form. I think a good captcha will solve this problem.

 

if GD's not installed, contact the server admin and request it be added. or move to a better host.

 

Yes you are right.

 

Ok here's a great tutorial on image verification (CAPTCHA), there's a download link of the script at the bottom
http://www.php-mysql-tutorial.com/user-authentication/image-verification.php

To get this working you need GD Library installed on your server, to check run <?php phpinfo(); ?> and look for reference on GD, you can install if yourself click here you need root access to the server if you do not have the permission to install or dont know how ask your server admin to install if for you.

Hope that helps

 

Thanx i have emailed my hosting server provider lets see i am waiting for his reply on the issue