import flash.display.StageScaleMode;
import flash.events.Event;
stage.scaleMode=StageScaleMode.NO_SCALE;
var stagew:int=stage.stageWidth;
var stageH:int=stage.stageHeight;
stage.addEventListener(Event.RESIZE,sizing);
function sizing(evt:Event):void
{
mc.scaleX=stage.stageWidth/stagew;
mc.scaleY=stage.stageHeight/stageH;
}