Alert class
<?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Script> import mx.controls.Alert; private function showAlert(event:Event):void { var alert:Alert = Alert.show("an alert."); } </mx:Script> <mx:Button id="button" label="Show Alert" click="showAlert(event)" /> </mx:Application>