title: clear checkboxes of selected options in jquery multiple select
body: <p>In below fiddle, I have a bootstrap modal and there is a Select Users MultipleSelect.  </p>
  
  <p>I need to clear the selection on modal close, like set the dropdown to defaults without any selection.</p>
  
  <p>For example, if I select user 1 and user 2, then on modal close, none should be selected. The previous selection must be gone.</p>
  
  <p>The code I am trying isn't helping me out and neither are any posts here on stack overflow.</p>
  
  <p>A little that I tried is this :</p>
  
  <pre><code>$("#usersDropDown option:selected").attr("checked",false);
  </code></pre>
  
  <p>And this :  </p>
  
  <pre><code>$("#usersDropDown option:selected").attr("selected",false);
  </code></pre>
  
  <p>And also this:</p>
  
  <pre><code>$("#usersDropDown option:selected").removeAttr("checked");
  </code></pre>
  
  <p>Please guide me what should I do ?</p>
  
  <p><a href="https://jsfiddle.net/5m966drd/1/" rel="nofollow noreferrer">Fiddle</a></p>