Adding the navigation
First of all, we will add the navigation bar to our web application. Before the start of the <body> tag, add the navigation bar, just as we did in the last chapter:
<nav class="navbar navbar-default navbar-fixed-top">
<div class="container">
<div class="navbar-header">
<a class="navbar-brand" href="webapp.html">
<img src="imgs/logo.png" class="img-responsive">
</a>
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#nav-menu" aria-expanded="false">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<!-- <a class="btn btn-primary navbar-btn pull-left" href="#" role="button">Sign up</a> -->
</div>
<div id="nav-menu" class=...
