<?php
if (isset($_POST['email'])) {
    // CHANGE THE TWO LINES BELOW
    $email_to = "contact@data1.nl";
    $email_subject = "Contact via Data1.nl";
    function died($error) {
        // your error code can go here
        echo "We are very sorry, but there were error(s) found with the form you submitted. ";
        echo "These errors appear below.<br /><br />";
        echo $error . "<br /><br />";
        echo "Please go back and fix these errors.<br /><br />";
        die();
    }
    // validation expected data exists
    if (!isset($_POST['first_name']) || !isset($_POST['last_name']) || !isset($_POST['email']) || !isset($_POST['telephone']) || !isset($_POST['comments'])) {
        died('We are sorry, but there appears to be a problem with the form you submitted.');
    }
    $first_name = $_POST['first_name']; // required
    $last_name = $_POST['last_name']; // required
    $email_from = $_POST['email']; // required
    $telephone = $_POST['telephone']; // not required
    $comments = $_POST['comments']; // required
    $verification = $_POST['verification']; // required

    $error_message = "";
    $email_exp = '/^[A-Za-z0-9._%-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';
    if (!preg_match($email_exp, $email_from)) {
        $error_message.= 'The Email Address you entered does not appear to be valid.<br />';
    }
    $string_exp = "/^[A-Za-z .'-]+$/";
    if (!preg_match($string_exp, $first_name)) {
        $error_message.= 'The First Name you entered does not appear to be valid.<br />';
    }
    if (!preg_match($string_exp, $last_name)) {
        $error_message.= 'The Last Name you entered does not appear to be valid.<br />';
    }
    if (strlen($comments) < 2) {
        $error_message.= 'The Comments you entered do not appear to be valid.<br />';
    }
    if($verification !== '11') {
        $error_message.= 'Verification failed<br />';
    }

    if (strlen($error_message) > 0) {
        died($error_message);
    }
    $email_message = "Formulier gegevens:.\n\n";
    function clean_string($string) {
        $bad = array("content-type", "bcc:", "to:", "cc:", "href");
        return str_replace($bad, "", $string);
    }
    $email_message.= "Voornaam: " . clean_string($first_name) . "\n";
    $email_message.= "Achternaam: " . clean_string($last_name) . "\n";
    $email_message.= "Email: " . clean_string($email_from) . "\n";
    $email_message.= "Telefoon: " . clean_string($telephone) . "\n";
    $email_message.= "Het Bericht: " . clean_string($comments) . "\n";
    // create email headers
    $headers = 'From: ' . $email_from . "\r\n" . 'Reply-To: ' . $email_from . "\r\n" . 'X-Mailer: PHP/' . phpversion();
    @mail($email_to, $email_subject, $email_message, $headers);
?>