title: bootstrap toggle. collapse not working
body: <p>i am following a tutorial on how to create a nav bar with drop down function but things are not working preperly.</p>
  
  <pre><code> &lt;!DOCTYPE html&gt;
   &lt;html lang="en"&gt;
   &lt;head&gt;
       &lt;title&gt;My Bootstrap&lt;/title&gt;
       &lt;meta charset="utf-8"&gt;
       &lt;meta name="viewport" content="width=device-width, initial-scale=1"&gt;
  
       &lt;link rel="stylesheet" href="bootstrap/css/bootstrap.min.css" /&gt;
       &lt;script       src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"&gt;      &lt;/script&gt;
        &lt;!--&lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"&gt;  &lt;/script&gt;--&gt;
       &lt;link rel="text/javascript" href="bootstrap/js/bootstrap.min.js" /&gt;
   &lt;/head&gt;
  
   &lt;body&gt;
  
       &lt;!-- Top Menu Bar--&gt;
       &lt;nav class="navbar navbar-inverse"&gt;
           &lt;div class="container-fluid"&gt;          
               &lt;!-- Logo --&gt;
               &lt;div class="navbar-header"&gt;
                   &lt;button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#mainNavBar"&gt;
                       &lt;span class="icon-bar"&gt;&lt;/span&gt;
                       &lt;span class="icon-bar"&gt;&lt;/span&gt;
                       &lt;span class="icon-bar"&gt;&lt;/span&gt;
                   &lt;/button&gt;
                   &lt;a href="#" class="navbar-brand"&gt;COLLAPSE NAVBAR&lt;/a&gt;
               &lt;/div&gt;
  
               &lt;!-- Menu Items --&gt;
               &lt;div class="collapse navbar-collapse" id="mainNavBar"&gt;
                   &lt;ul class="nav navbar-nav"&gt;
                       &lt;li class="active"&gt;&lt;a href="#"&gt;Home&lt;/a&gt;&lt;/li&gt;
                       &lt;li&gt;&lt;a href="#"&gt;About&lt;/a&gt;&lt;/li&gt;
                       &lt;li&gt;&lt;a href="#"&gt;Contact&lt;/a&gt;&lt;/li&gt;
                   &lt;/ul&gt;  
               &lt;/div&gt;
  
           &lt;/div&gt;
       &lt;/nav&gt;
  
       &lt;!-- Main Content --&gt;
       &lt;div class="container"&gt;
  
  
  
       &lt;/div&gt;
   &lt;/body&gt;
  
   &lt;/html&gt;
  </code></pre>
  
  <p>the toggle function is working properly but the menu items are not collapsing upon clicking the button.
  base on the tutorial this is a jquery issue. i tried using the updated one but still didn't work. i also tried downloading the jquery file  still didn't work.
  can someone tell me what wrong with this code?</p>