Mathjs
An extensive math library for JavaScript and Node.js
Xdate
A Modern JavaScript Date Library
Auto Numeric
autoNumeric is a jQuery plugin that automatically formats currency (money) and numbers as you type on form inputs. It supports most International numeric formats and currency signs including those used in Europe, North and South America, Asia and India (lakhs**).
jQuery Number
Easily format numbers for display use. Replace numbers inline in a document, or return a formatted number for other uses.
Store
A better way to use localStorage and sessionStorage
Big.js
A small, fast JavaScript library for arbitrary-precision decimal arithmetic.
Sprintf.js
sprintf.js is a complete open source JavaScript sprintf implementation.
Poly
Small, fast, awesome. The only ES5-ish set of polyfills (shims) you can mix-and-match because they're individual AMD modules.
Date
Date() for humans
Tiny Color
Fast, small color manipulation and conversion for JavaScript
Inversify Js
A powerful and lightweight inversion of control container for JavaScript & Node.js apps powered by TypeScript.
Placeholders.js
A JavaScript polyfill for the HTML5 placeholder attribute
Augment.js
Modern JavaScript in your IE
Hitch
A lightweight engine that allows you to hitch new capabilities to the browser (prollyfill).
Ratio.js
Rational numbers for Javascript
Respond
A fast & lightweight polyfill for min/max-width CSS3 Media Queries (for IE 6-8, and more)
Svgeezy
Allows for automatic Image fallbacks for browsers that can't handle SVGs