<html>
<head>
<meta http-equiv="content-type" content="text/html" charset="UTF-8">
<script type="text/javascript" >
var picArr=new Array("1.jpg","2.jpg","3.jpg") ;
var index=0;
//展示下一张图片
function next(){
index++;
if (index==picArr.length){
index=0;
}
document.getElementById("img1").src=picArr[index];
}
//展示上一张图片
function precious(){
index--;
if (index<0){
index=picArr.length-1;
}
document.getElementById("img1").src=picArr[index];
}
</script>
<body>
<img id="img1"src="1.jpg" width="500" height="300"/><br/>
<input type="button" value="下一张" onclick="next()"/>
<input type="button" value="上一张" onclick="precious()"/>
<body>
</html>
原文：http://www.cnblogs.com/sosomark/p/5188500.html