process from submit

?
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) {
?die ("The reCAPTCHA wasn't entered correctly. Go back and try it again." .
?"(reCAPTCHA said: " . $resp->error . ")");
?}

from page


<script type='text/javascript'>
	var RecaptchaOptions = { theme : 'red', lang : 'en' , tabindex : 5 };
</script>
<script type="text/javascript" src="http://api.recaptcha.net/challenge?k=plublic key "></script>

<noscript>
<iframe src="http://api.recaptcha.net/noscript?k=plublic key" height="300" width="500" frameborder="0"></iframe><br/>
<textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
<input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
</noscript>