Tiny Number Format JavaScript Library – numer.js
A super tiny (1kb minified) JavaScript library for converting, formatting and manipulating numbers.
JavaScript & CSS number format
Convenient Multi-language Number Formatting Library – numbro
numbro is a robust number formatting JavaScript library used for converting, formatting, and manipulating numbers with support for currency, time, percentage, and much more.
Convert Numbers To Roman Numerals – Romanice
A dependency-free JavaScript library that converts Arabic numbers (1, 2, 3, …) to roman numerals (I, II, III, …) and vice versa.