$(document).ready(function() {

  $('#module_searchwidget input[name=\'filter_name\']').keydown(function(e) {
    if (e.keyCode == 13) {
      url = 'index.php?route=product/search';

      var filter_name = $('input[name=\'filter_name\']').attr('value')

      if (filter_name) {
        url += '&filter_name=' + encodeURIComponent(filter_name);
      }

      location = url;
    }
  });

});