//定時更換圖片：  調用：smileChange.start();  smileChange.stop();
var smileChange = {
            start: function () {
                var that = this;//鍐呭眰鐨勫唴灞傚嚱鏁扮殑this浼氬嚭闂
                this.intervalId = setInterval(function () {
                    clearTimeout(that.timeoutId);
                    $(
 
".third .smile img").attr("src", "img/smile-on-2.png");
                    that.timeoutId = setTimeout(function () {
                        $(".third .smile img").attr("src", "img/smile-off-2.png");
                    }, 500);
                    //console.log("start  timeout ID "+that.timeoutId);
                }, 1000);


            },
            stop: 
 
function () {
                console.log("stop timeout id" + this.timeoutId);
                clearInterval(this.intervalId);
                clearTimeout(this.timeoutId);
                console.log("stop interval id" + this.intervalId);
            },
            changing: 0,
            intervalId: 
 
0,
            timeoutId: 0
        }

js定時更換圖片