ADDED_TO_STAGE From http://www.inazumatv.com/contents/archives/177

ADDED_TO_STAGE.as

package  {
	import flash.display.MovieClip;
	import flash.events.Event;
	public class SomeClass extends MovieClip {
		public function SomeClass(){
			super();
			if (stage) init(null);
			else addEventListener(Event.ADDED_TO_STAGE, init);
		}
		private function init(evt:Event) : void {
			if (evt != null)
				removeEventListener(Event.ADDED_TO_STAGE, init);
			trace (stage.stageWidth);
		}
	}	
}