The professional solution is no interactive forms where you combine client (DOM) scripting with server side scripting like PHP.
Exellent book (with code),
Build*Your*Own AJAX Web*Applications - SitePoint Books
that also gives you
a soft introduction to OOP.
Note that AJAX (also called extended JavaScript) has taken JavaScript to a new serious level with OO features. You need to know DOM building to do any serious web application building using the AJAX engine.