<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="//code.jquery.com/jquery-1.11.1.min.js"></script>
<nav class="navbar navbar-default" role="navigation">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<div class="navbar-collapse collapse">
<ul class="nav navbar-nav navbar-left">
<li><a href="#">Left 1</a></li>
<li class="dropdown">
<a class="dropdown-toggle" data-toggle="dropdown" href="#">left 2 (SimpleDropDown)
<span class="caret"></span></a>
<ul class="dropdown-menu">
<li><a href="#">Page 1-1</a></li>
<li><a href="#">Page 1-2</a></li>
<li><a href="#">Page 1-3</a></li>
</ul>
</li>
<li><a href="#about">Left 3</a></li>
<li class="dropdown"><a href="#" class="dropdown-toggle" data-toggle="dropdown">Left 4(AdvancedDropdown)<b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Dropdown Link 1</a></li>
<li><a href="#">Dropdown Link 2</a></li>
<li><a href="#">Dropdown Link 3</a></li>
<li class="divider"></li>
<li class="dropdown dropdown-submenu"><a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown Link 4</a>
<ul class="dropdown-menu">
<li><a href="#">Dropdown Submenu Link 4.1</a></li>
<li><a href="#">Dropdown Submenu Link 4.2</a></li>