select value from dropdown and submit form in jquery
<div class="dropdown show">
<a class="btn btn-filter dropdown-toggle" href="#" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
<select name="sort_by" id='short_by' class="selection">
<option value="">Short By</option>
<option value="popularity">By Popularity</option>
<option value="ASC">By Name A - Z</option>
<option value="DESC">By Name Z - A</option>
</select>
</a>
</div>
<script type="text/javascript">
$(document).ready(function(){
$('#short_by').change(function(){
$('#filterform').submit(); // form id
});
});
</script>