<link href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<div id="myNav" class="overlay">
<a href="javascript:void(0)" class="closebtn" onclick="closeNav()">×</a>
<div class="overlay-content">
<a href="#">About</a>
<a href="#">Services</a>
<a href="#">Clients</a>
<a href="#">Contact</a>
</div>
</div>
<h2>Fullscreen Overlay Nav Example</h2>
<p>Click on the element below to open the fullscreen overlay navigation menu.</p>
<p>In this example, the navigation menu will slide in, from left to right:</p>
<span style="font-size:30px;cursor:pointer" onclick="openNav()">☰ open</span>