jQuery is a lightweight, "write less, do more", JavaScript library. The purpose of jQuery is to make it much easier to use JavaScript on your website. jQuery takes a lot of common tasks that require many lines of JavaScript code to accomplish, and wraps them into methods that you can call with a single line of code. jQuery also simplifies a lot the complicated things from JavaScript, like AJAX calls and DOM manipulation. The jQuery library contains the following features: HTML/DOM manipulation CSS manipulation HTML event methods Effects and animations AJAX Utilities Tip: In addition, jQuery has plugins for almost any task out there.