Specify Event object as a parameter in the event handler function
<?xml version="1.0"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Script> import mx.controls.Alert; private function myEventHandler(e:Event):void { Alert.show("An event of type " + e.type + " occurred."); } </mx:Script> <mx:Button id="b1" label="Click Me" click="myEventHandler(event)" /> </mx:Application>