select value from dropdown and submit form in jquery

1<div class="dropdown show">
2      <a class="btn btn-filter dropdown-toggle" href="#" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
3       <select name="sort_by" id='short_by' class="selection">
4          <option value="">Short By</option>
5          <option value="popularity">By Popularity</option>
6          <option value="ASC">By Name A - Z</option>
7          <option value="DESC">By Name Z - A</option>
8          </select> 
9       </a>
10</div>  
11
12<script type="text/javascript">
13       $(document).ready(function(){
14          $('#short_by').change(function(){    
15            $('#filterform').submit(); // form id
16        });
17      });   
18  </script>