function formcheck() {

  if(document.Feedbackform.Vorname.value == "")  {
    alert("Enter your firstname please!");
    document.Feedbackform.Vorname.focus();
    return false;
    }
	
  if(document.Feedbackform.Nachname.value == "")  {
    alert("Enter your name please!");
    document.Feedbackform.Nachname.focus();
    return false;
    }
	
  if(document.Feedbackform.Email.value == "") {
    alert("Enter your E-Mail address, please!");
    document.Feedbackform.Email.focus();
    return false;
    }

  if(document.Feedbackform.Betreff.value == "") {
    alert("Enter the subject of your E-Mail, please!");
    document.Feedbackform.Betreff.focus();
    return false;
    }	

  if(document.Feedbackform.Nachricht.value == "") {
    alert("Enter your message text, please!");
    document.Feedbackform.Nachricht.focus();
    return false;
    }

alert("Thank you for your message!");
return true;
}