js 自动轮播图

var count= 0;

var timerBig,Ttimer;

functionautoPlay () {

    timerBig= setInterval(function() {

            count++;

            var c = 1000; //每次偏移的left

            var d = 10; //段数

            var t = 0; //存储当前步数

            var b= content.offsetLeft;//获取当前left值

            Ttimer= setInterval(function () {

                t++;

                content.style.left= b- c/ d* t+ "px";

                if (t>=d) {

                    //清除计时器

                            clearInterval(Ttimer);

                            //循环

                            if(count>=4){

                                    content.style.left= 0;

                                    count= 0;

                            }

                        //切换span的背景

                        for (var i= 0; i< spans.length; i++) {

                            if (count== i) {

                                spans[i].className= "select" 

                                } else{

                                spans[i].className= "unselect" 

                            }

                    }

        }

},50)

},2000);

}