Deferred and promise are part of jQuery since version 1.5 and they help in handling asynchronous functions like Ajax.

JQuery is a fast, small, and feature-rich JavaScript library. It makes things like HTML document traversal and manipulation, event handling, animation, and Ajax much simpler with an easy-to-use API that works across a multitude of browsers.

In this article we’ll look at how we can use jquery to manipulate, traverse and select DOM elements at ease. Before we start we have to download jquery and load it in your HTML document

Writing jQuery in CoffeeScript, further simplifies the syntax. The jQuery(function($)) can be written as jQuery($) -> or simply $ ->.