<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
*{margin:0;padding:0;list-style:none;}
a{text-decoration: none;color: #fff;}
#flash{ 730px;height: 454px;margin: 100px auto;position: relative;cursor: pointer;}
#pic li{position: absolute;top: 0;left: 0;z-index: 1;display: none;}
#num{position: absolute;left: 40%;bottom: 10px;z-index: 2}
#num li{float: left; 20px;height: 20px;border-radius: 50%;background: #666;margin: 3px;line-height: 20px;text-align: center;color: #fff;}
#num li.active{background: #f00;}
.arrow{height: 60px; 30px;line-height: 60px;text-align: center;display: block;position: absolute;top:45%;background-color: rgba(0,0,0,0.3);z-index: 3;display: none;}
.arrow:hover{background: rgba(0,0,0,0.7);}
#flash:hover .arrow{display: block;}
#left{left: 2%;}
#right{right: 2%;}
</style>
<script type="text/javascript">
function $(id) {
return typeof id==='string'?document.getElementById(id):id;
}
window.onload=function(){
var index=0;
var timer=null;
var pic=$("pic").getElementsByTagName("li");
var num=$("num").getElementsByTagName("li");
var flash=$("flash");
var left=$("left");
var right=$("right");
//单击左箭头
left.onclick=function(){
index--;
if (index<0) {index=num.length-1};
changeOption(index);
}
//单击右箭头
right.onclick=function(){
index++;
if (index>=num.length) {index=0};
changeOption(index);
}
//鼠标划在窗口上面，停止计时器
flash.onmouseover=function(){
clearInterval(timer);
}
//鼠标离开窗口，开启计时器
flash.onmouseout=function(){
timer=setInterval(run,2000)
}
//鼠标划在页签上面，停止计时器，手动切换
for(var i=0;i<num.length;i++){
num[i].id=i;
num[i].onmouseover=function(){
clearInterval(timer);
changeOption(this.id);
}
}
//执行计时器之前，清理计时器，以免造成浪费
if(timer){
clearInterval(timer);
timer=null;
}
//定义计时器
timer=setInterval(run,2000)
//封装函数run
function run(){
index++;
if (index>=num.length) {index=0};
changeOption(index);
}
//封装函数changeOption
function changeOption(curindex){
console.log(index)
for(var j=0;j<num.length;j++){
pic[j].style.display="none";
num[j].className="";
}
pic[curindex].style.display="block";
num[curindex].className="active";
index=curindex;
}
}
</script>
</head>
<body>
<div id="flash">
<ul id="pic">
<li style="display:block"><img src="http://img13.360buyimg.com/da/jfs/t2242/262/578407619/87636/4ffe0c5/56187ed2Nfed9a5b3.jpg" alt=""></li>
<li><img src="http://img13.360buyimg.com/da/jfs/t2143/111/577347825/96150/e27180bd/561889b3N42ee62b5.jpg" alt=""></li>
<li><img src="http://img20.360buyimg.com/da/jfs/t1825/234/1750370913/97529/b9229832/560b5ad3N054605f7.jpg" alt=""></li>
<li><img src="http://img10.360buyimg.com/da/jfs/t2026/215/573306345/95654/a0211937/5618a735N1b3d8423.jpg" alt=""></li>
<li><img src="http://img20.360buyimg.com/da/jfs/t2065/362/579832759/78899/6f349917/5618c680N3752bacc.jpg" alt=""></li>
<li><img src="http://img10.360buyimg.com/da/jfs/t2023/45/384256123/101565/9b6e5daf/5604bdceN8c7d2ccf.jpg" alt=""></li>
</ul>
<ol id="num">
<li class="active">1</li>
<li>2</li>
<li>3</li>
<li>4</li>
<li>5</li>
<li>6</li>
</ol>
<a href="javascript:;" class="arrow" id="left"><</a>
<a href="javascript:;" class="arrow" id="right">></a>
</body>
</html>