title: display alert after button is clicked
body: <p>I have a button that pops up an alert "Hello" after being clicked.
  It works fine for the first click but after I close the alert and I clicked the button again, the alert doesn't shows. Please help.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
  &lt;meta name="viewport" content="width=device-width, initial-scale=1"&gt;
  &lt;link rel="stylesheet"
   href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"&gt;
  &lt;script
   src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"&gt;&lt;/script&gt;
  &lt;script
   src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"&gt;&lt;/script&gt;
  &lt;style&gt;
  .hidden {
   display: none;
  }
  &lt;/style&gt;
  &lt;title&gt;Show Alert&lt;/title&gt;
  &lt;/head&gt;
  
  &lt;body id="page-top" data-spy="scroll" data-target=".navbar-fixed-top"&gt;
   &lt;div class="container"&gt;
  
    &lt;div class="row"&gt;
     &lt;div class="alert alert-success hidden" id="success-alert"&gt;
      &lt;button type="button" class="close" data-dismiss="alert"&gt;x&lt;/button&gt;
      &lt;span class="glyphicon glyphicon-ok"&gt;&lt;/span&gt; Hello
     &lt;/div&gt;
    &lt;/div&gt;
  
    &lt;div class="row"&gt;
     &lt;button id="btn" type="button" class="btn btn-default"&gt;Open
      Alert&lt;/button&gt;
    &lt;/div&gt;
   &lt;/div&gt;
  
   &lt;script type="text/javascript"&gt;
    $(document).ready(function() {
     $("#btn").click(function() {
      $('#success-alert').removeClass('hidden');
     });
  
    });
   &lt;/script&gt;
  &lt;/body&gt;
  
  &lt;/html&gt;</code></pre>
  </div>
  </div>
  </p>