flash as3 不同浏览器获取正确的舞台宽度和高度

public class Detective extends Sprite
{
public static var APP_WIDTH:int = 900;//480;
public static var APP_HEIGHT:int = 600;//800;
public static var designwidth:Number = 900;//720;
public static var designheight:Number = 600;//1280;
public static var stagewidth:Number;
public static var stageheight:Number;

private static var _instance:Detective;




public static function getInstance():Detective
{
if(!_instance)
{
throw("please use getInstance");
}
return _instance;
}
public function Detective()
{
stage.scaleMode = StageScaleMode.NO_SCALE;
stage.align = StageAlign.TOP;
var menu: ContextMenu = new ContextMenu();
var item: ContextMenuItem = new ContextMenuItem(Config.appendVersion());

menu.customItems.push(item);?
menu.hideBuiltInItems();

this.contextMenu = menu;

if(stage){
addHandler(null);
trace(? "stage!=null"+"stagewidth="+stage.stageWidth+"stageheight="+stage.stageHeight);//ie9+,chrome浏览器时，会执行这里
}else{
trace(?"stage==null"+"stagewidth="+stage.stageWidth+"stageheight="+stage.stageHeight);//ie6-8浏览器时，会执行这里
addEventListener(Event.ADDED_TO_STAGE,addHandler);

}


}
private function addHandler(event:Event):void
{
if(event != null){
removeEventListener(Event.ADDED_TO_STAGE,addHandler);
}

if(stage.stageWidth == 0 || stage.stageHeight == 0){

trace( "stage.stageWidth == 0"+"stagewidth="+stage.stageWidth+"stageheight="+stage.stageHeight);//ie6-8浏览器时，会执行这里
stage.addEventListener(Event.RESIZE,resizeHandler);
}
else{
init();
}
}
private function resizeHandler(event:Event):void
{
if(stage.stageWidth > 0 && stage.stageHeight > 0){

trace(?"stage.stageWidth == 0"+"stagewidth="+stage.stageWidth+"stageheight="+stage.stageHeight);//ie6-8浏览器时，会执行这里
stage.removeEventListener(Event.RESIZE,resizeHandler);
init();
}
}
private function init():void

{

//根容器已经添加到stage,可以正确获取舞台宽高 了 ?（兼容所有浏览器）

stagewidth = stage.stageWidth;
stageheight = stage.stageHeight;

}

}