<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet"
href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<div class="dropdown">
<button class="btn btn-default dropdown-toggle" type="button" data-toggle="dropdown">Dropdown
<span class="caret"></span></button>
<ul class="dropdown-menu dropdown-menu-right">
<li><a href="#">PHP</a></li>
<li><a href="#">CSS</a></li>
<li><a href="#">C</a></li>
<li><a href="#">JavaScript</a></li>
</ul>
</div>
</div>
</body>
</html>
