w3 css cdn code example
Example: css cdn
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<link rel="stylesheet" type="text/css" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">