MooTools is a compact, modular, Object-Oriented JavaScript framework designed for the intermediate to advanced JavaScript developer. It allows you to write powerful, flexible, and cross-browser code with its elegant, well documented, and coherent API.

MooTools code respects strict standards and doesn’t throw any warnings. It’s well commented and has meaningful variable names: a joy to browse and a snap to understand.

MooTools is released under the Open Source MIT license, which gives you the possibility to use it and modify it in every circumstance

You can Download release 1.11 here.

Read Documentation here.