Hitch
A lightweight engine that allows you to hitch new capabilities to the browser (prollyfill).
Numeral
A javascript library for formatting and manipulating numbers.
Stringformatter
JS string formatter that supports objects, currency, date/time, decimals, and more supports easy extension and garbage collection ... goes far beyond sprintf approach.
Bignumber.js
A JavaScript library for arbitrary-precision decimal and non-decimal arithmetic
Sugar
A Javascript library for working with native objects.
Date
Date() for humans
Moment
Parse, validate, manipulate, and display dates in javascript.
Dayjs
⏰ Day.js 2KB immutable date library alternative to Moment.js with the same modern API
Respond
A fast & lightweight polyfill for min/max-width CSS3 Media Queries (for IE 6-8, and more)
Angled Edges
:triangular_ruler: Quickly create angled section edges using only Sass
HTML5shiv
This script is the defacto way to enable use of HTML5 sectioning elements in legacy Internet Explorer.
ES5 Shims
ECMAScript 5 compatibility shims for legacy JavaScript engines
Decimal.js
An arbitrary-precision Decimal type for JavaScript
Console.message
Console messages for cool kids
Datejs
Datejs is an open-source JavaScript Date Library.
Flexie
Legacy support for the CSS3 Flexible Box Model
Underscore String
String manipulation extensions for Underscore.js javascript library.