css垂直居中
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
<style type="text/css">
#wrap{width: 500px;height: 200px;border: 1px solid black;}
i{height: 100%;vertical-align: middle;display: inline-block;}
span{vertical-align: middle;display: inline-block;width: 490px;font-size: 0px;}
span a{padding:5px ;display: inline-block;background: gray;margin-right:10px ;margin-bottom: 2px;font-size: 20px;}
</style>
</head>
<body>
<div id="wrap">
<i></i>
<span>
<a href="">aaaa</a>
<a href="">bbbb</a>
<a href="">ccce</a>
<a href="">dddd</a>
<a href="">eeee</a>
<a href="">aaaa</a>
<a href="">aaaa</a>
<a href="">bbbb</a>
<a href="">ccce</a>
<a href="">dddd</a>
<a href="">eeee</a>
<a href="">aaaa</a>
<a href="">aaaa</a>
<a href="">bbbb</a>
<a href="">ccce</a>
<a href="">dddd</a>
<a href="">eeee</a>
<a href="">aaaa</a>
</span>
</div>
</body>
</html>
