AngularJS lets you write client-side web applications as if you had a smarter browser. It lets use good old HTML (or HAML, Jade and friends!) as your template language and lets you extend HTML’s syntax to express your application’s components clearly and succinctly
The most advanced responsive front-end framework in the world. Quickly create prototypes and production code for sites and apps that work on any kind of device.
Advanced HTML5 Mobile App Framework. A beautiful front-end framework for developing hybrid mobile apps in HTML5. Best friends with AngularJS.
Give your JS App some Backbone with Models, Views, Collections, and Events
Select2 is a jQuery based replacement for select boxes. It supports searching, remote data sets, and infinite scrolling of results.
Ajax.org Cloud9 Editor
Simple HTML5 Charts using the <canvas> tag
Universal video embed.
Sinatra inspired web development framework for node.js -- insanely fast, flexible, and simple