在流程图中菱形代表判断，圆角矩形代表开始和结束，平行四边形代表内容。
清除定时器：
function clearT()
{
clearInterval(clearTime)
}
开启定时器：
function openT()
{
clearTime = setInterval(change,2000)
}
setInterval（控制的函数，时间一般用毫秒表示）
轮播：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<link rel="stylesheet" type="text/css" href="./lunbo.css">
</head>
<body>
<div id="main">
<div id="left" onclick="houtui()"></div>
<div id="center"></div>
<div id="right" onclick="change()"></div>
</div>
<script>
var imgDiv = document.getElementById('center');
var imgBg= imgDiv.style
var number = 1
function change()
{
if(number > 3)
{
number = 1;
}
imgBg.background = 'url(./p_w_picpaths/'+ number +'.jpg)';
number++;
}
function houtui()
{
if(number<1)
{
number = 3
}
imgBg.background = 'url(./p_w_picpaths/'+ number +'.jpg)';
number--
}
var clearTime = setInterval(change,2000)
清除定时器函数
function clearT()
{
clearInterval(clearTime)
}
开启函数定时器
function openT()
{
clearTime = setInterval(change,2000)
}
</script>
</body>
</html>
