for the response ..firstly you have to call the particular action of urs url!!..
than you have to generate the response there!
than print the result on your action!.
and youe code must as follow
<script>
$(document).ready(function() {
$('#source').change(function() {
var Filter = $(this).val();
$.ajax({
type: "POST",
url: "complete url",
data: {Filter: Filter},
success: function(result) {
$("#target").html(result);
}
});
});
});
</script>