function checkform( thisform ) {
  if (thisform.name.value == "" || isNaN(thisform.name.value) == false) {
	alert ("Bitte gib Deinen Vor- und Nachnamen an!");
    thisform.name.select();
	thisform.name.focus();
	return false;
  }
  if (thisform.email.value == "") {
	alert ("Bitte gibt Deine E-Mail-Adresse an!");
    thisform.email.select();
	thisform.email.focus();
	return false;
  } 
  if(thisform.email.value) {
    var exclude=/[^@\-\.\w]|^[_@\.\-]|[\._\-]{2}|[@\.]{2}|(@)[^@]*\1/;
    var check=/@[\w\-]+\./;
    var checkend=/\.[a-zA-Z]{2,3}$/;
    if(((thisform.email.value.search(exclude) != -1)||(thisform.email.value.search(check)) == -1)||(thisform.email.value.search(checkend) == -1)){
      alert("Bitte gib eine gültige E-Mail-Adresse an!");
      thisform.email.select();
	  thisform.email.focus();
	  return false;
    }
  } 
  if (thisform.telefon.value == "") {
	alert ("Bitte gib Deine Telefonnummer an!");
    thisform.telefon.select();
	thisform.telefon.focus();
	return false;
  }   
return true;
}