<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>mb5u.com</title>
<style type="text/css">
div {
position:absolute;
top:50%;
left:50%;
margin:-150px 0 0 -200px;
400px;
height:300px;
border:1px solid red;
}
</style>
</head>
<body>
<div>- Div CSS布局 常见问题</div>
</body>
</html>