打开网页时，弹出小窗口，N秒后自动关闭。
<!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>
</head>
<script>
var newwin = window.open("pop.html","","width=300,height=200");
setTimeout("newwin.window.close()",3000);
</script>
<body>
主页fdgdfgdfgdfgfdg
</body>
</html>
pop.html 是要弹出的窗口文件。
