<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>IE居中不生效-</title>
</head>
<body>
<div style="width:400px;margin:0px auto;border:1px solid red;height:100px;"> </div>
</body>
</html>
以上代碼在IE中居中不生效
加個<!DOCTYPE html>就可以了：
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<title>IE居中不生效-</title>
</head>
<body>
<div style="width:400px;margin:0px auto;border:1px solid red;height:100px;"> </div>
</body>
</html>