function chkFormular()
{
 if(document.Formular.Nachname.value == "")  {
   alert("Please write your name!");
   document.Formular.Nachname.focus();
   return false;
  }
    if(document.Formular.strasse.value == "")  {
   alert("Please write your street-name!");
   document.Formular.strasse.focus();
   return false;
  }
  if(document.Formular.plz.value == "")  {
   alert("Please write your zip-code!");
   document.Formular.plz.focus();
   return false;
  }
  if(document.Formular.ort.value == "")  {
   alert("Please write your town!");
   document.Formular.ort.focus();
   return false;
  }
  if(document.Formular.elektrischepost.value == "")  {
   alert("Please write your e-mail adress!");
   document.Formular.elektrischepost.focus();
   return false;
  }
  if(document.Formular.elektrischepost.value.indexOf('@') == -1) {
   alert("this is not an e-mail adress!");
   document.Formular.elektrischepost.focus();
   return false;
   }     
  if(document.Formular.telefon.value == "")  {
   alert("Please write your telefon-nummer!");
   document.Formular.telefon.focus();
   return false;
  }
  if(document.Formular.kommentare.value == "")  {
   alert("what do you want???");
   document.Formular.kommentare.focus();
   return false;
  }
    if(document.Formular.check.value == "")  {
   alert("Please fill out the check-box!");
   document.Formular.check.focus();
   return false;
  }
}