function checkform() {


 
 
var error = false;
var agberror = false;
var plzerror = false;
var plz5error = false;
var preisvonerror = false;
var aplzerror = false;
var error_message = "This data is required:\n\n";



    if (document.formular.benutzernameneu.value == '') {
  error = true;
  error_message += "-please chose a username\n";
 }
 
 
    if (document.formular.kennwortneu.value == '') {
  error = true;
  error_message += "-please chose a password\n";
 }
 
 
    if (document.formular.plz.value == '') {
  error = true;
  error_message += "-ZIP-Code is required\n";
 }
 

 if (document.formular.email.value == '') {
  error = true;
  error_message += "-EMail-Address is required\n";
 } 
 else if (document.formular.email.value.indexOf("@") == -1) {
  error = true;
  error_message += "-EMail is not valid\n";
 }
 	
 
 if (error) {
  error_message += "\nPlease fill out the required fields.";
  

  
  alert(error_message);

  return false; 
 } else {
  return true;  
 }
}