图片定时轮播
代码：
<!DOCTYPE html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<style type="text/css">
/*图片定时轮播*/
.picture{display:none;}
/*去列表标记及字体样式*/
.list{list-style-type:none;}
</style>
<script>
var li = document.getElementById('ppt').getElementsByTagName("li");
var num = 0;
var len = li.length;
setInterval(function todo() {
li[num].style.display = "none";
num = ++num == len ? 0 : num;
li[num].style.display = "inline-block";
}, 2000);
</script>
</head>
<body>
<div id="ppt">
<ul class="list">
<li><img src="#" width="#" height="#"/></li>
<li class="picture"><img src="#" width="#" height="#" /></li>
<li class="picture"><img src="#" width="#" height="#"/></li>
<li class="picture"><img src="#" width="#" height="#"/></li>
<li class="picture"><img src="#" width="#" height="#" /></li>
<li class="picture"><img src="#"width="#" height="#"/></li>
</ul>
</div>
</body>
</html>