Captcha is good to reduce spam. One of most popular captcha used is recaptcha.
This is how it looks like. Familiar?
captcha
To implement it is very easy. Will take less than 10 minutes of your time.
1. Get your public and private key
https://www.google.com/recaptcha/admin/create
2. Include class file
Download recaptcha library file for PHP (with some sample files)
3. Insert code in form page
1 2 3 4 5 6 7 8 | <form method="post" action="verify.php">
<?php
require_once('recaptchalib.php');
$publickey = "your_public_key"; // you got this from the signup page
echo recaptcha_get_html($publickey);
?>
<input type="submit" />
</form> |
4. Insert code to validate code in process page
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | require_once('recaptchalib.php'); $privatekey = "your_private_key"; $resp = recaptcha_check_answer ($privatekey, $_SERVER["REMOTE_ADDR"], $_POST["recaptcha_challenge_field"], $_POST["recaptcha_response_field"]); if (!$resp->is_valid) { // What happens when the CAPTCHA was entered incorrectly die ("The reCAPTCHA wasn't entered correctly. Go back and try it again." . "(reCAPTCHA said: " . $resp->error . ")"); } else { // Your code here to handle a successful verification } |