Verifier CAPTCHAT en JS

<?php
  if (chk_crypt($_POST['code'])) 
     echo "Bravo";
     else echo "Erreur";
?>

 if ($_POST['code'] == $_SESSION['cryptcode'])
//captacha valide
else
//captacha invalide

<?php 
$cryptinstall="./crypt/cryptographp.fct.php";
include $cryptinstall; 
?>


<?php
$TO = "em.smith@laposte.net";

$h = "From: " . $TO;

$message = "";

while (list($key, $val) = each($HTTP_POST_VARS)) 
{
$message .= "$key : $val\n";
}
?>
<?php
	if ($_POST['code'] == $_SESSION['cryptcode']) 
	echo	mail($TO, $subject, $message, $h);
	else echo "Clé de sécutité incorecte";
?>