What is jQuery?

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. With a combination of versatility and extensibility, jQuery has changed the way that millions of people write JavaScript.

In plain English, jQuery is a JavaScript library that allows you change, edit, animate, and create features of your websites.  You can do these animations and changes based on timing, or based on user interaction.  So, it can really add an impressive dynamic to your site.  JavaScript is often a complex programming language, so it can require a lot of in-depth knowledge to include on your website.  jQuery uses common sense functions that allow you simplify these complex lines of code into single-lines of code.

jQuery describes itself as a “write less, do more” JavaScript library.