collapsible navigation bar become invisible on mobile screen - css

Question

I am trying to implement twitter bootstrap collapsible navigation bar. On Desktop navigation bar is visible but on mobile screen it's not visible.
Here is View Part
<div class="masthead clearfix">
<div class="inner">
<h3 class="masthead-brand"><img src="/x/img/X.png" style="width:80px; position:relative; top:-20px;"></img></h3>
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<div id="navbar" class="navbar-collapse collapse">
<ul class="nav navbar-nav navbar-right" style="margin-top:15px;background-color:rgba(255,255,255,.4)">
<li class="active"><a class="call_us btn btn-default no-rounded btn-hollow" th:text="${'+91 444}" style="cursor:default; pointer-events:none;"> Call Us 555</a></li>
<li ><a th:href="#{/X}" href="#">X</a></li>
<li><a th:href="#{/Y}" href="#">Y</a></li>
<li><a th:href="#{/Z}" href="#">Z</a></li>
<li><a th:href="#{/T}" href="#">C</a></li>
<li class="active"><a th:href="#" href="#">Blog</a></li>
<!--li>Help</li-->
</ul>
</div><!--/.nav-collapse -->
</div>
</div>
</div>
Can some one help me to fix this issue. I have included collapse.js in my path.

Answer 1

You're missing the navbar class which is the first line of the default navigation in Bootstrap. See Docs.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" />
<div class="masthead clearfix">
<div class="inner">
<h3 class="masthead-brand"><img src="http://placehold.it/350x150" style="width:80px; position:relative; top:-20px;"></img></h3>
<nav class="navbar navbar-default">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar"> <span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<div id="navbar" class="navbar-collapse collapse">
<ul class="nav navbar-nav navbar-right" style="margin-top:15px;background-color:rgba(255,255,255,.4)">
<li class="active"><a class="call_us btn btn-default no-rounded btn-hollow" th:text="${'+91 444}" style="cursor:default; pointer-events:none;"> Call Us 555</a>
</li>
<li><a th:href="#{/X}" href="#">X</a>
</li>
<li><a th:href="#{/Y}" href="#">Y</a>
</li>
<li><a th:href="#{/Z}" href="#">Z</a>
</li>
<li><a th:href="#{/T}" href="#">C</a>
</li>
<li class="active"><a th:href="#" href="#">Blog</a>
</li>
<!--li>Help</li-->
</ul>
</div>
<!--/.nav-collapse -->
</div>
</nav>
</div>
</div>