上下轮播

<body>

</body>

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>