<?php
$muster="/^[a-zA-Z0-9-_.]+@[a-zA-Z0-9-_.]+\.[a-zA-Z]{2,4}$/";
if (!empty($_POST['name'] && $_POST['mail'] && $_POST['nachricht']) && preg_match($muster, $_POST['mail'])>0) {
$mailbody=$_POST['nachricht'];
$Email=$_POST['mail'];
if (!is_numeric($_POST['name'])) {
switch($_POST['anrede']){...