import mx.events.CalendarLayoutChangeEvent;
private function update(evt:CalendarLayoutChangeEvent):void {
var MILLISECONDS:int = 1000;
var SECONDS:int = 60;
var MINUTES:int = 60;
var HOURS:int = 24;
var diff:Number = endDate.selectedDate.getTime() - startDate.selectedDate.getTime();
var days:int = int(diff/(MILLISECONDS*SECONDS*MINUTES*HOURS));
display.text = days.toString();
}