代码如下：span标签里的数字不会显示
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script type="text/javascript">
var time=5;
function timecount(){
document.getElementById("js")=time;
time--;
i=setTimeout(timecount,1000);
if(time==0){
clearTimeout(i);
window.open('http://wwww.baidu.com');
}
}
function goback(){
window.history.go(-1);
}
timecount();
</script>
</head>
<body>
<p>操作成功</p><br />
<span id="js"></span>秒后跳回指定页面
<a href="javascript:goback()">返回之前页面</a>
</body>
</html>