JavaScript Library for Objective Sound Programming

Create, from the Midgard Project is a comprehensive web editing interface for Content Management Systems. It is designed to provide a modern, fully browser-based HTML5 environment for managing content. Create can be adapted to work on almost any content management backend.

Tempus is designed to be a full replacement to the Date class inside Javascript, to solve the frustration of missing features and broken functionality. Tempus offers over 230 methods ranging from string methods to date maths and assertions to iterators, all packed into a tiny 4.5kb (minified and gzipped) package.

pdf.js is an HTML5 technology experiment that explores building a faithful and efficient Portable Document Format (PDF) renderer without native code assistance.

Outlet is a programming language. It is Lisp-like in nature and compiles to both javascript and lua.

Ender is a full featured package manager for your browser.
It allows you to search, install, manage, and compile front-end javascript packages and their dependencies for the web.

Dust is a JavaScript templating engine designed to provide a clean separation between presentation and logic without sacrificing ease of use. It is particularly well-suited for asynchronous and streaming applications.

Strategies to accelerate development with Backbone.js

Backbone.js extension that connects backbone models with relational associations.

Get and set relations (one-to-one, one-to-many, many-to-one) for Backbone models

Sammy is a tiny javascript framework built on top of jQuery inspired by Ruby's Sinatra.

Rubyish extensions to Javascript