Prototype JavaScript

Prototype is a JavaScript Framework that aims to ease development of dynamic web applications.

http://www.prototypejs.org/

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.

prototype.js is a JavaScript library initially written by Sam Stephenson. This amazingly well thought and well written piece of standards-compliant code takes a lot of the burden associated with creating rich, highly interactive web pages that characterize the Web 2.0 off your back.

Developers familiar with the Ruby programming language will notice an intentional similarity between Ruby's built-in classes and many of the extensions implemented by this library. That's not surprising since prototype.js is a spinoff and is directly influenced by the requirements of the Ruby on Rails framework.

As far as browser support goes, prototype.js tries to support Internet Explorer (Windows) 6.0+, Mozilla Firefox 1.5+, Apple Safari 1.0+, and Opera 9+. Supporting these browsers also cause some other browsers that share their rendering engines to be supported as well, like Camino, Konqueror, IceWeasel, Netscape 6+, SeaMonkey, etc.