How do active web pages work? Describe with a small example.

Active Web Pages:

An active document is not completely specified through the server. Instead an active document contains a computer program which understands how to compute and display values. While a browser requests an active document, therefore the server returns a copy of the program which the browser should run locally. While this runs the active document program can interact with the user and change the display continuously. Hence the contents of an active document are never fixed- they can carry on changing as long as the user permits the program to run. Following is the illustration of active document by using java applets.

An example applied that counts the number of times user clients a buttons.