<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<nav class="navbar navbar-inverse nav_custom">
<div class="container-fluid">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#myNavbar">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Company Name</a>
</div>
<div class="collapse navbar-collapse" id="myNavbar">
<form class="navbar-form navbar-left" >
<div class="input-group">
<input type="text" class="form-control" placeholder="Search">
<div class="input-group-btn">
<button class="btn btn-default" type="submit">
<i class="glyphicon glyphicon-search"></i>
</button>
</div>
</div>
</form>
<ul class="nav navbar-nav navbar-right">
<li class="active"><a href="#">Home</a></li>
<li class="dropdown bigmenu">
<a class="dropdown-toggle" data-toggle="dropdown" href="#">Page 1 <span class="caret"></span></a>
<ul class="dropdown-menu subbignav row">
<li class="col-md-4">
<ul>
<li class="nav-header"><h5>Sub Cateogry</h5></li>
<li class="divider"></li>
<li><a href="#">Page 1-1</a></li>