Captcha is a type of challenge-response test used in computing to determine whether or not the user is human or spammer's robot. A CAPTCHA involves one computer (a server) which asks a user to complete a test. While the computer is able to generate and grade the test, it is not able to solve the test on its own. Because computers are unable to solve the CAPTCHA, any user entering a correct solution is presumed to be human.
Protect your forms from spammers with these free php spam protection scrips
Image Validator is a GPL CAPTCHA php script to stop spam on any form: comment areas, sign-ups, shopping carts - any area of your website where you fear the evil spammers may target.
1. Apache 1 or 2
2. PHP 4 or 5
3. GD 2 with truetype support
0. Unpack this package.
1. You may edit _config.php file located in imgval directory.
2. You may copy some TrueType fonts in imgval/fonts directory.
2. Upload or copy imgval directory to browsable directory.
3. Open imgval/index.php in your browser for testing.
IV. INTEGRATION NOTES
In tag, 'src' parametter should be linked with imgval/code.php.
To prevent cache images you may add some unique parameter.
Example: " />
Your should start a session in the response PHP file. In the valid action
PHP source code you should verify MD5 sum of the input-code-field-value
with session variable named __img_code__
if (md5($_POST['code']) == $_SESSION['__img_code__'])
echo "Valid code";
echo "Invalid code";