Ember.js : A JavaScript framework for creating ambitious web applications
Slate : Slate is a completely customizable framework for building rich text editors.
Slate lets you build rich, intuitive editors like those in Medium, Dropbo...
The Dojo Toolkit : Dojo saves you time and scales with your development process, using web standards as its platform. It’s the toolkit experienced developers turn to for...
MooTools : MooTools is a compact, modular, Object-Oriented JavaScript framework designed for the intermediate to advanced JavaScript developer. It allows you to ...
script.aculo.us : script.aculo.us provides you with
easy-to-use, cross-browser user
interface JavaScript libraries to make
your web sites and web applications fly.
Raphaël is a small JavaScript library that should simplify your work with vector graphics on the web. If you want to create your own specific chart or image crop and rotate widget, for example, you can achieve it simply and easily with this library.