title: Toggle button collapse not working in Bootstrap navbar in bootstrap
body: <p>Here is my navbar created by bootstrap
  Why the button doesn't work in small sizes?</p>
  
  <p>I've compared my navbar with bootstrap several times. why it doesn't work?</p>
  
  <pre><code>&lt;div class="navbar-wrapper"&gt;
      &lt;div class="container container-class&gt;
          &lt;nav class=" navbar navbar-fixed-top "&gt;
          &lt;div class="navbar-inner "&gt;
          &lt;div class="header-customer-support-nayan07 "&gt;
              &lt;h4&gt;Telephone&lt;/h4&gt;
              &lt;p&gt;982144556633+&lt;/p&gt;
          &lt;/div&gt;
          &lt;div class="collapse navbar-collapse "&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 class="dropdown "&gt;
                      &lt;a href="# "&gt;Pages
                       &lt;span class="caret "&gt;&lt;/span&gt;&lt;/a&gt;
                      &lt;ul class="dropdown-menu "&gt;
                          &lt;li&gt;&lt;a href="# "&gt;Page 1-1&lt;/a&gt;&lt;/li&gt;
                          &lt;li&gt;&lt;a href="# "&gt;Page 1-2&lt;/a&gt;&lt;/li&gt;
                          &lt;li&gt;&lt;a href="# "&gt;Page 1-3&lt;/a&gt;&lt;/li&gt;
                      &lt;/ul&gt;
                  &lt;/li&gt;
                  &lt;li&gt;&lt;a href="# "&gt;Products&lt;/a&gt;&lt;/li&gt;
                  &lt;li&gt;&lt;a href="# "&gt;Blog&lt;/a&gt;&lt;/li&gt;
                  &lt;li&gt;&lt;a href="# "&gt;Contacts&lt;/a&gt;&lt;/li&gt;
              &lt;/ul&gt;
          &lt;/div&gt;
          &lt;button class="navbar-toggle " aria-controls="navbar " aria-expanded="true " data-target=".nav-collapse " data-toggle="collapse " type="button "&gt;
              &lt;span class="sr-only "&gt;Toggle navigation&lt;/span&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;/div&gt;
  </code></pre>