<!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">
<h2>Bootstrap Nesting Button Groups and Dropdown Menu</h2>
<div class="btn-group">
<button type="button" class="btn btn-primary">PHP</button>
<button type="button" class="btn btn-primary">CSS</button>
<div class="btn-group">
<button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
Programming <span class="caret"></span></button>
<ul class="dropdown-menu" role="menu">
<li><a href="#">C</a></li>
<li><a href="#">C++</a></li>
</ul>
</div>
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