<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>背景图切换</title>
<style type="text/css">
#wrap{
300px;height: 225px;
margin: 100px auto 0px;
position: relative;
}
img{
display: block;
300px;
height: 100%;
}
span{
font-size: 30px;
}
#last{
position: absolute;
right: 40px;bottom: 5px;
}
#next{
position: absolute;
right: 5px;bottom: 5px;
}
</style>
</head>
<body>
<div id="wrap">
<img src="img/4.jpg">
<span id="last"><</span>
<span id="next">></span>
</div>
<script type="text/javascript">
//获取元素
var img = document.getElementsByTagName('img')[0];
var btn1 = document.getElementById('last');
var btn2 = document.getElementById('next');
//图片数组
var images = ['img/4.jpg','img/5.jpeg','img/6.jpg','img/9.jpg'];
//添加事件
//定义变量用来记录当前下标
var index= 0;
btn1.onclick = function (){
index++;
if (index > 3) {
index = 0;
}
//修改图片路径
img.src = images[index];
}
btn2.onclick = function (){
index--;
if (index < 0) {
index = 3;
}
//修改图片路径
img.src = images[index];
}
</script>
</body>
</html>