function mail_reset()
{
  document.forms['mail'].addemail.value = "";
}

  function auswahl(b, c)
  {
    if(b == "erste")
    {
      document.getElementById("zweite").style.display = "none";
      document.getElementById("dritte").style.display = "none";

      document.getElementById(b).style.display = "block";
    }

    if(b == "zweite")
    {
      document.getElementById("erste").style.display = "none";
      document.getElementById("dritte").style.display = "none";

      document.getElementById(b).style.display = "block";
    }

    if(b == "dritte")
    {
      document.getElementById("erste").style.display = "none";
      document.getElementById("zweite").style.display = "none";

      document.getElementById(b).style.display = "block";
    }
  }