http://prototype.conio.net/

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.

• Download the latest version (1.4.0)
• Just the .js, please
• Browse the Subversion repository
  Checkout with svn co http://dev.rubyonrails.org/svn/rails/spinoffs/prototype

Related Projects

• Ruby on Rails, featuring integrated Prototype support
• script.aculo.us, Thomas Fuchs’ incredible effects and controls library built on Prototype
• Rico, rich Ajax components and effects built on Prototype
• Behaviour, a cool mechanism for cleaning up your HTML