Sprintf.js
sprintf.js is a complete open source JavaScript sprintf implementation.
Bignumber.js
A JavaScript library for arbitrary-precision decimal and non-decimal arithmetic
CSS Parent Selector
CSS4 parent selector based on jQuery
Moment
Parse, validate, manipulate, and display dates in javascript.
Stringformatter
JS string formatter that supports objects, currency, date/time, decimals, and more supports easy extension and garbage collection ... goes far beyond sprintf approach.
Date
Date() for humans
Flexie
Legacy support for the CSS3 Flexible Box Model
ES5 Shims
ECMAScript 5 compatibility shims for legacy JavaScript engines
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.
Numeral
A javascript library for formatting and manipulating numbers.
Datejs
Datejs is an open-source JavaScript Date Library.
Args.js
Create javascript functions with optional, default, grouped and named parameters.
Angled Edges
:triangular_ruler: Quickly create angled section edges using only Sass
Mathjs
An extensive math library for JavaScript and Node.js
Klass
a utility for creating expressive classes in JavaScript
Babel
Babel is a compiler for writing next generation JavaScript.