timer = setInterval(mar,30);
        //鼠標移上去清除時鐘
        box.onmouseover = function(event){
            clearInterval(timer);
            event.stopPropagation();
            //這裏是阻止冒泡，不加要冒泡到body上面，鼠標在body上面就會clearInterval(timer);
            box.onmouseout = function(event){
                timer = setInterval(mar, 30);
             event.stopPropagation();
            }
        };
        //用jq方式寫
        /*$(box).on(‘mouseover‘,function(){
            clearInterval(timer);
        })*/
//        $(box).mouseover(function(event){
//            clearInterval(timer);
//            event.stopPropagation();
//            $(box).mouseout(function(e){
//                timer = setInterval(mar,30);
//                e.stopPropagation();
//            })
//        });

真是奇怪，js可以，jq卻開啟了多個定時器，誰能解答一下