bootstrap IE兼容
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<script src="http://apps.bdimg.com/libs/html5shiv/3.7/html5shiv.min.js"></script>
<script src="http://apps.bdimg.com/libs/respond.js/1.4.2/respond.min.js"></script>