A simple utility JQuery plugin that converts a select element generated from `wp_dropdown_categories` into a classic jump menu/drop down navigation.

jquery.jump-menu.js

;(function($) {

$.fn.jumpMenu = function(options) {
  // Creatues a jumpmenu using a form containing wp_dropdown_categories() and a submit input
  return this.each(function() {
    var form = $(this);

    $('input[type=submit]', form).hide();

    var categories = $('select#cat', form);

    categories.change(function() {
      form.submit();
    });
  });
};

})(jQuery);