I am trying to reset the stage width to its orriginal size when user click on button after changes to the browser zoom level.

However this is restting the width of stage according to the new zoom level with the result that the stage size increase even more. I tried using a variable to use as holder of orriginal stageWidth but how to reset it to that width?

stage.align = StageAlign.TOP_LEFT;
stage.scaleMode = StageScaleMode.NO_SCALE;
var mystageW:uint=stage.stageWidth;

mybtn.addEventListener(MouseEvent.CLICK,update);

function update(e:MouseEvent):void {

var zoom:uint=stage.stageWidth-mystageW;

if (stage.stageWidth!=mystageW) {

ExternalInterface.call("function( id, w ) { document.getElementById(id).style.width = w + 'px'; }", ExternalInterface.objectID, stage.stageWidth );

}
}