flash删除所有子元素避免内存泄露
public static function removeAllChildren(container:DisplayObjectContainer):void{try{var child:DisplayObject;for (var i:Number = container.numChildren - 1; i >= 0; i--) {child = container.getChildAt(i);if (child is DisplayObjectContainer && !(child is Loader/*跨域引用图片时,子元素不允许访问,否则报沙箱安全移除*/)) {removeAllChildren(DisplayObjectContainer(child));}container.removeChild(child);}}catch(e:Error){Alert.show("Util.removeAllChildren异常:"+e);}}?