Underscore is a utility-belt library for JavaScript that provides a lot of the functional programming support that you would expect in Prototype.js (or Ruby), but without extending any of the built-in JavaScript objects. It’s the tie to go along with jQuery’s tux, and Backbone.js’s suspenders.

Backbone.js

http://backbonejs.org/

Backbone.js

Backbone.js gives structure to web applications by providing models with key-value binding and custom events, collections with a rich API of enumerable functions, views with declarative event handling, and connects it all to your existing API over a RESTful JSON interface.

Javascript Tutorial

http://www.codecademy.com/tracks/javascript

Javascript Tutorial

“JavaScript is a programming language that makes websites interactive. HTML & CSS will let you make nice looking webpages, but they’ll be static. JavaScript allows you to ask your user to input information, move elements around on the page, and for to make your website more modern and functional.”