<?php
if(isset($_POST['emailAdress']) && isset($_POST['emailSubject']) && isset($_POST['emailMessage']) && filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)){
    $emailAdress = $_POST['emailAdress'];
    $emailSubject = $_POST['$emailSubject'];
    $emailMessage = $_POST['$emailMessage'];

//send email
    mail("martin.niklaus@gmx.ch" .$emailAdress, $emailMessage);
}?>