What is the Closure Library?

The Closure Library is a broad, well-tested, modular, and cross-browser JavaScript library. You can pull just what you need from a large set of reusable UI widgets and controls, and from lower-level utilities for DOM manipulation, server communication, animation, data structures, unit testing, rich-text editing, and more.

The Closure Library is server-agnostic, and is intended for use with the Closure Compiler.

Who uses Closure Library?

The Closure Library serves as the base JavaScript library for many Google products, including:

Search	Gmail	Maps	Docs	Sites	Books	Blogger	Calendar	Google+	Photos

Now that the Closure Library is open source, more and more developers outside Google are integrating the library in their own projects.

What can the Closure Library do for me?

If you are developing a large or growing application, you may benefit from the Closure Library's breadth. A well-tested library can insulate you from cross-browser compatibility issues and the minutiae of client-side programming, letting you focus on the fun stuff.

How do I start?