Dependent dropdowns

hi, it is possible to recreate this example for dependent drop-downs(http://www.dse.se/pulsar/AjaxDemo/AjaxDemo.html?countryId_old=119®\.\.\.\)

i have 4 tables : country, region, city and customer with dependent foreign key. id_loc.customer ->id_loc.city->id_loc.region->id_loc.country i have only generated 4 scaffold for the tables. thanks