<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css">
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap-theme.min.css">
<link rel="stylesheet" href="dist/css/bootstrap-submenu.min.css">
<script src="//code.jquery.com/jquery-2.1.1.min.js" defer></script>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js" defer></script>
<script src="dist/js/bootstrap-submenu.min.js" defer></script>
</head>
<body>
...
</body>
</html>
Enable Bootstrap-submenu via JavaScript:
$('.dropdown-submenu > a').submenupicker();