function changeDuration()
{
	// ACHTUNG! regionCode wird in den lokalen datepicker js definiert!
    
    if(typeof regionCode != "undefined") {
		var sep = $.datepicker.regional[regionCode].dateFormat.substring(2,3);
		var currentDateFormat = $.datepicker.regional[regionCode].dateFormat;
	 	var eFrom=$("input[@name=dateFrom]");
	 	var sep1 = eFrom.val().substring(2,3);
	 	var sep2 = eFrom.val().substring(5,6);
    } else {
    	var sep = $.datepicker._defaults.dateFormat.substring(2,3);
		var currentDateFormat = $.datepicker._defaults.dateFormat;
	 	var eFrom=$("input[@name=dateFrom]");
	 	var sep2 = eFrom.val().substring(2,3);
	 	var sep1 = eFrom.val().substring(5,6);
    }
    
 
 	var eTo=$("input[@name=dateTo]");
 	
 	var eFromTime=$("input[@name=dateFromTime]");
 	var eToTime=$("input[@name=dateToTime]");

 	if((isNaN(sep1))&&(isNaN(sep2)))
 	{
 		var dFrom = $.datepicker.parseDate(currentDateFormat, eFrom.val()); 	
 		var dTo = $.datepicker.parseDate(currentDateFormat, eTo.val());
 	
 		var timeFrom = dFrom.getTime();
 		var timeTo = dTo.getTime();
 		
 		var duration = (timeTo-timeFrom) / (1000 * 60 * 60 * 24);
 		
 		if(eFromTime && eFromTime.length > 0)
 		var iFromHours = parseInt(eFromTime.val().substring(0,2), 10);
 		if(eToTime && eToTime.length > 0)
 		var iToHours = parseInt(eToTime.val().substring(0,2), 10);
 		if(eFromTime && eFromTime.length > 0)
 		var iFromMinutes = parseInt(eFromTime.val().substring(2,4), 10);
 		if(eToTime && eToTime.length > 0)
 		var iToMinutes = parseInt(eToTime.val().substring(2,4), 10);
 		
 		var additionalDays = 0;
 		if(iToHours > iFromHours){
 			additionalDays = 1;
 		}
 		else{
 			if(iToHours == iFromHours && iToMinutes > iFromMinutes){
 				additionalDays = 1;
 			}
 		}
 		
 		duration = duration + additionalDays;
 		
 		//
 		// nochmal kurz runden, da ab 40 Tagen Abstand kleine Fehler reinkommen 	
 		duration = Math.round(duration);
 		
 		//
 		// anahme und abgabe am gleichen tag -> mietdauer 1 tag, nicht 0
 		if(duration == 0){
 			duration = 1;
 		}
 		//
 		// wenn duration negativ, dann erst gar nicht anzeigen
 		if(duration < 0){
 				document.getElementById('duration').innerHTML = '';
 		}
 		else{
 			if(document.getElementById('duration'))
 				document.getElementById('duration').innerHTML = duration.toString();
 		}
 		

		// trigger onchange der felder:
		eFrom.trigger('change');
		eTo.trigger('change');	
	}  							 		
}