function validateFormData (form) {

	var RefString="1234567890";

	var Counter = 0;

	enteredPLZ = form.plz.value;

	if(enteredPLZ.length == 5){
		for (Count=0; Count < 5; Count++)  {
			TempChar= enteredPLZ.substring (Count, Count+1);
			if (RefString.indexOf (TempChar, 0)==-1)
			Counter++;
		}
	} else {
		Counter = 1;
	}

	if(Counter === 0){
		if (document.getElementById('melding').style.display== 'block'){
			document.getElementById('melding').style.display='none';
			document.getElementById('melding2').style.display='block';
		}
	} else {
		//if (document.getElementById('melding').style.display== 'none'){
			document.getElementById('melding').style.display='block';
			document.getElementById('melding2').style.display='none';
		//}
		return false;
	}
}