Bootstrap and Jquery linked in web page. If the visitor to your site has already downloaded the Bootstrap's files from the same CDN while visiting the other sites, it will be loaded from the browser's cache instead of re-downloading, which leads to faster loading time.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Basic Bootstrap Template</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
<!-- Optional Bootstrap theme -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap-theme.min.css">
</head>
<body>
<h1>Hello, world!</h1>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
</body>
</html>