Add Javascript to PDF Form to control combo boxes and do Validation

I have a pdf form that I have designed it needs javascript to make it work properly. There are several combo boxes, some combo boxes will need to be populated based on the contents of one or more other combo boxes. Based on the combo boxes selected a part number should be generated as well a a price. The end product will be delivered as a un password protected pdf that could be edited in the future. The javascript should be well documented with notes that explain the purpose of functions and variables.