<?php
error_reporting(E_NOTICE);
function valid_email($str) {
    return (!preg_match("/^([a-z0-9\+_\-]+)(\.[a-z0-9\+_\-]+)*@([a-z0-9\-]+\.)+[a-z]{2,6}$/ix", $str)) ? FALSE : TRUE;
}

if ($_POST['name'] != '' && $_POST['email'] != '' && valid_email($_POST['email']) == TRUE && strlen($_POST['comment']) > 1) {
    $to = $_POST['receiver'];
    $headers = 'From: '.$_POST['email'].''."\r\n".'Reply-To: '.$_POST['email'].''."\r\n".'X-Mailer: PHP/'.phpversion();
    $subject = "Contact Form";
    $message = htmlspecialchars($_POST['comment']);
    
    if (mail($to, $subject, $message, $headers)) {
        echo 1; // SUCCESS
    } else {
        echo 2; // FAILURE - server failure
    }
} else {
    echo 3; // FAILURE - not valid email

}
?>