My navigation menu button is not functioning correctly. I am currently working on this project using CodePen, so Bootstrap is already integrated into the code.
<div class="navbar-header">
<button type="button" class="btn navbar-toggle" data-toggle="collapse" data-target="#mainNavBar">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a href="#" class="navbar-brand"> Nasr Almansoob </a>
</div>
<div class="collapse navbar-collapse" id="mainNavBar">
<ul class="nav navbar-nav">
<li class="active"> <a href="#"> Home </a></li>
<li><a href="#"> About Me </a></li>
<li> <a href="#"> Aspirations </a> </li>
</ul>
</div>