hamburger not shown in menu collapsed using bootstrap - html

Question

I am using bootstrap 3 with the standard css shipped with the package.
I have built a menu out of the basic structure provided in the examples and built this HTML:
<nav class="navbar navbar-default navbar-static-top">
<div class="container-fluid">
<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="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>-->
<a class="navbar-brand" href="index.php"><img src="images/logo_small.png" alt="Montglane"></a>
</div>
<div id="navbar" class="navbar-collapse collapse">
<ul class="nav navbar-nav navbar-left">
<li class="active voce">Home</li>
<li class="dropdown voce" id="movimenti">
Movimenti <span class="caret"></span>
<ul class="dropdown-menu">
<li>Banca</li>
<li>Carta di credito</li>
<li>Timesheet</li>
<!--<li>Something else here</li>-->
<!--
<li role="separator" class="divider"></li>
<li class="dropdown-header">Nav header</li>
<li>Separated link</li>
<li>One more separated link</li>
-->
</ul>
</li>
<li class="dropdown voce" id="report">
Report <span class="caret"></span>
<ul class="dropdown-menu">
<li>Banca</li>
<li>Carta di credito</li>
<li>Geco</li>
<li>Fatture</li>
</ul>
</li>
<li class="dropdown voce" id="anagrafiche">
Anagrafiche <span class="caret"></span>
<ul class="dropdown-menu">
<li>Banche</li>
<li>Carte</li>
<li>Clienti</li>
<li>Commesse</li>
<li>Tipi Movimenti</li>
</ul>
</li>
</ul>
<!--<ul class="nav navbar-nav navbar-right">
<li></li>
</ul> -->
<p class="navbar-text navbar-right"><?php echo $_SESSION['nome_est']; ?></p>
</div><!--/.nav-collapse -->
</div>
</nav>
It works but when it comes to small viewports it stopped showing the hamburger. I have inspected the code and the menu options are there to be shown but I miss the three lines button to toggle menu visibility. What kind of mistake did I do?
Note that I didn't apply any custom css or js by now.

Answer 1

Now as answer ;)
You commented the HTML section of the button. See line 4 to 10. Button including 3 spans icon-bar.

Answer 2

you have commented hamburger menu section
<link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<nav class="navbar navbar-default navbar-static-top">
<div class="container-fluid">
<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="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="index.php"><img src="images/logo_small.png" alt="Montglane"></a>
</div>
<div id="navbar" class="navbar-collapse collapse">
<ul class="nav navbar-nav navbar-left">
<li class="active voce">Home</li>
<li class="dropdown voce" id="movimenti">
Movimenti <span class="caret"></span>
<ul class="dropdown-menu">
<li>Banca</li>
<li>Carta di credito</li>
<li>Timesheet</li>
<!--<li>Something else here</li>-->
<!--
<li role="separator" class="divider"></li>
<li class="dropdown-header">Nav header</li>
<li>Separated link</li>
<li>One more separated link</li>
-->
</ul>
</li>
<li class="dropdown voce" id="report">
Report <span class="caret"></span>
<ul class="dropdown-menu">
<li>Banca</li>
<li>Carta di credito</li>
<li>Geco</li>
<li>Fatture</li>
</ul>
</li>
<li class="dropdown voce" id="anagrafiche">
Anagrafiche <span class="caret"></span>
<ul class="dropdown-menu">
<li>Banche</li>
<li>Carte</li>
<li>Clienti</li>
<li>Commesse</li>
<li>Tipi Movimenti</li>
</ul>
</li>
</ul>
<!--<ul class="nav navbar-nav navbar-right">
<li></li>
</ul> -->
<p class="navbar-text navbar-right"><?php echo $_SESSION['nome_est']; ?></p>
</div><!--/.nav-collapse -->
</div>
</nav>