Which are the three js files that are required to setup Backbone.js?

The three JavaScript files required to set up Backbone.js are:

1. Underscore.js: Backbone.js depends on Underscore.js for utility functions such as map, reduce, each, and more. Underscore.js provides functional programming helpers without extending any built-in objects.
2. jQuery.js (optional): While not strictly required, Backbone.js often pairs with jQuery for DOM manipulation and AJAX calls. Backbone.js can work without jQuery, but it’s commonly used together for convenience.
3. Backbone.js: This is the Backbone.js library itself. It provides the framework for building single-page applications by providing models with key-value binding and custom events, collections with a rich API of enumerable functions, views with declarative event handling, and more.