URL: http://www.prototypejs.org/


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.

Lastest version (as on 21 April 2008) is 1.6.


Tutorials available at http://www.prototypejs.org/learn