Pure JavaScript

Localizing JavaScript apps with jQuery.i18n — in this post you will meet the jQuery.i18n library, created by the Wikimedia foundation. You will see it in action and learn how to prepare translation files, perform pluralization, work with gender, and more.
Libraries for translating JavaScript apps — this article provides a nice summary of the most popular i18n and l10n libraries for JavaScript. You will learn about the Globalize, jQuery.i18n, i18next, and Polyglot.js solutions.
JSON L10n — learn about the usage of JSON translation files in Web.