Babel
Babel is a compiler for writing next generation JavaScript.
Mathjs
An extensive math library for JavaScript and Node.js
Decimal.js
An arbitrary-precision Decimal type for JavaScript
Poly
Small, fast, awesome. The only ES5-ish set of polyfills (shims) you can mix-and-match because they're individual AMD modules.
Inversify Js
A powerful and lightweight inversion of control container for JavaScript & Node.js apps powered by TypeScript.
Timezone Js
Timezone-enabled JavaScript Date object. Uses Olson zoneinfo files for timezone data.
Placeholders.js
A JavaScript polyfill for the HTML5 placeholder attribute
Tiny Color
Fast, small color manipulation and conversion for JavaScript
Nerdamer
a symbolic math expression evaluator for javascript
Bignumber.js
A JavaScript library for arbitrary-precision decimal and non-decimal arithmetic
Xdate
A Modern JavaScript Date Library
jQuery Number
Easily format numbers for display use. Replace numbers inline in a document, or return a formatted number for other uses.
Selectivizr
Selectivizr is a JavaScript utility that emulates CSS3 pseudo-classes and attribute selectors in Internet Explorer 6-8.
Sugar
A Javascript library for working with native objects.
Ratio.js
Rational numbers for Javascript
Placeholder Shiv
Tiny polyfill for the placeholder form element attribute. Requires Prototype.js.
CSS Parent Selector
CSS4 parent selector based on jQuery