PHP 4 Applications is a class set for implementing a GUI with forms, listviews, etc, using event driven programming helped by the "Remote Scripting" method.

The goals of PHP 4 Applications are to:
- Do all the work in PHP without having to take care of generating HTML, capturing events on the server side, processing this events using PHP , and returning the response to the client side without reloading the page.
- Have a set of classes to create many types of GUI elements, setting the event handling by assigning names to each event of interest, and processing the events doing something like to modify the state of the object in the server side and returning the response in an hidden iframe to redraw the GUI element on the client side.
- Open a door for a future tool, lik "Visual-PHP", that simplifies the construction and generation of Web based GUI without dealing with too many technical details.

The main class is p4a_Application, a container of buttons, forms, labels or panels, that is also a contanier itself and can be made visible or not like a frame in Visual Basic.