Create dependent drop down list using AJAX, PHP and MySQL.

The project include developing a dependent drop down list using AJAX, PHP and MySQL for 4 dependent drop down list. The data of all drop down lists are get from database. When the four lists are setup, the product is loaded from database without page refresh or reload. Instruction for customize the script for less or more drop down is required. Also the script must allow insert more than one drop down list in same page if needed. Design of the tables fields is provided.