Build a Website

Hello I want some one create a page for me as this example : [login to view URL] this old example used jquery to check username availableity and also for load cities and salaries I need you to create same this page but by using pure ajax and json (without jquery) I have 3 json files first json file return the cities for a country second json file return salaries for a country Third json file return avaliable username is 0/1 the files in attachments thank you