<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
*{
border: 0;
padding: 0;
margin: 0;
}
#box{
font-size: 20px;
10000px;
height: 20px;
background: red;
line-height: 20px;
vertical-align:middle;
}
</style>
</head>
<body>
<div id="box">我也不知道为什么 </div>
<script type="text/javascript"></script>
</body>
</html>