Painless JavaScript Using Prototype

Another JavaScript Library...

Prototype is a JavaScript framework that aims to ease development of dynamic web
applications. Featuring a unique, easy-to-use toolkit for class-driven
development and the nicest Ajax library around, Prototype is quickly becoming
the codebase of choice for web application developers everywhere.

Read more here:
http://www.sitepoint.com/article/painless-javascript-prototype

And here it is a very nice diagram of this library's methods and ... all that:
http://www.snook.ca/archives/000531.php

( http://www.snook.ca/archives/prototype1440.png )