MOUSE_OVER/MOUSE_OUT与ROLL_OVER/ROLL_OUT的区别

MOUSE_OVER和MOUSE_OUT除了对监听该事件的控件作出响应，同时也对该控件的所有子控件(拥有该事件)进行响应

ROLL_OVER和ROLL_OUT则相反，只响应监听该事件的控件

package
{
    import flash.display.Sprite;
    import flash.display.StageScaleMode;
    import flash.events.MouseEvent;
    
    public class Sample0814 extends Sprite
    {
        public function Sample0814()
        {
            stage.scaleMode = StageScaleMode.NO_SCALE;
            
            var box:Sprite = new Sprite();
            box.graphics.beginFill(0xCCCCCC);
            box.graphics.drawRect(0,0,200,200);
            box.graphics.endFill();
            box.x = box.y = 50;
//          box.addEventListener(MouseEvent.MOUSE_OVER,mouseOverHandler);
//          box.addEventListener(MouseEvent.MOUSE_OUT,mouseOutHandler);
            box.addEventListener(MouseEvent.ROLL_OVER,rollOverHandler);
            box.addEventListener(MouseEvent.ROLL_OUT,rollOutHandler);
            this.addChild(box);
            
            var item:Sprite = new Sprite();
            item.graphics.beginFill(0xFF0000);
            item.graphics.drawRect(0,0,80,80);
            item.graphics.endFill();
            item.x = item.y = 60;
            box.addChild(item);
        }
        
        private function mouseOverHandler(event:MouseEvent):void
        {
            trace("mouse over");
        }
        
        private function mouseOutHandler(event:MouseEvent):void
        {
            trace("mouse out");
        }
        
        private function rollOverHandler(event:MouseEvent):void
        {
            trace("roll over");
        }
        
        private function rollOutHandler(event:MouseEvent):void
        {
            trace("roll out");
        }
    }
}