<body>
<div><img id="tu" src="lun1.jpg" width="800px" height="498px"></div>
<input type="button" onclick="pro()" value="上一张">
<input type="button" onclick="nex()" value="下一张">
</body>
<script>
var arr=["轮播1.jpg","轮播2.jpg","轮播3.jpg"];
var tu=document.getElementById("tu");
var num=0;
// 上一张
function pro(){
num--;
console.log(num);
if (num<0){
num=2;
}
if(num>=0&&num<=arr.length-1){
tu.setAttribute("src",arr[num]);
}
}
//下一张
function nex(){
num++;
console.log(num);
if (num>arr.length-1){
num=0;//从0开始
}
if(num<=arr.length-1){
tu.setAttribute("src",arr[num]);
}
}
var te=setInterval(nex,1000);
tu.onmouseover = function() {
window.clearInterval(te);
};
tu.onmouseout = function() {
te = setInterval(nex, 1000);
};
</script>
原文：http://www.cnblogs.com/1039595699TY/p/5515931.html