function showInput (select) {
  var wert = select.options[select.options.selectedIndex].value;
  if (wert == "rueckruf" || wert == "termin" || wert == "infoabend") {
    $('address_id').fade();
    $('telefon_id').appear();
  }
  else {
    $('address_id').appear();
    $('telefon_id').fade();
  }
}