Empty "<div class="modal-backdrop fade in"></div>"
<p>I have problem with modal in my code, there is not appear and div with class "modal-backdrop fade in" is empty.</p>

<pre><code>&lt;body&gt;
&lt;button type="button" title="Usuń" class="deleteButton btn btn-default btn-xs pull-right"&gt;Usuń&lt;/button&gt;

&lt;div id="confirm" class="modal hide fade"&gt;
&lt;div class="modal-body"&gt;
    Are you sure?
&lt;/div&gt;
&lt;div class="modal-footer"&gt;
    &lt;button type="button" data-dismiss="modal" class="btn btn-primary" id="delete"&gt;Delete&lt;/button&gt;
    &lt;button type="button" data-dismiss="modal" class="btn"&gt;Cancel&lt;/button&gt;
&lt;/div&gt;
</code></pre>

<p>
  </p>

<pre><code>$("body").on('click', "button.deleteButton", function (e) {
  var clickedButton = $(this);
  e.preventDefault();
  $('#confirm').modal({ backdrop: 'static', keyboard: false })
    .one('click', '#delete', function () {
    clickedButton.attr("disabled", true);    
  });
});
</code></pre>

<p>Here is my fiddle:
<a href="https://jsfiddle.net/cjdtzsha/" rel="nofollow">https://jsfiddle.net/cjdtzsha/</a></p>

<p>What can be reason for it?</p>