Learn jQuery Online — 72 Interactive Lessons with Live Preview

jQuery is still one of the most widely deployed JavaScript libraries on the web. Millions of websites built over the past decade use jQuery for DOM manipulation, event handling, AJAX requests, and animation. Whether you are learning web development for the first time, maintaining a legacy codebase, or brushing up on selectors and traversal before a job interview, the jQuery Playground gives you a structured path through the entire library — with live, editable examples at every step.

The playground is organized into 16 chapters covering the full jQuery curriculum: Getting Started, Selectors, Events, Hide & Show, Fading, Sliding, Animation, Chaining, DOM Get & Set, DOM Add & Remove, CSS Manipulation, Traversing, AJAX, Utilities, Deferred & Promises, and Plugin Basics. Each chapter contains between 1 and 7 lessons, for a total of 72 lessons. Every lesson includes a concept explanation, a working code example you can edit immediately, and a live preview that rebuilds automatically as you type.

The editor handles mixed HTML and JavaScript code the way jQuery code naturally looks — HTML markup at the top of the file, jQuery logic inside a <script> tag below. The syntax highlighter colors HTML tags, attributes, strings, jQuery's $ symbol, and JavaScript keywords separately. Line numbers stay in sync with scrolling. Error messages from uncaught exceptions appear in the editor's error bar and in the console panel.

Each lesson's preview runs in a sandboxed iframe with jQuery 3.7.1 loaded from the jsDelivr CDN. The iframe is rebuilt on every code change (debounced at 400ms), so you always see a fresh execution — no stale state from a previous run. The console panel captures console.log, console.warn, and console.error from inside the iframe and displays them in the parent, so you do not need to open browser DevTools to see output.

Progress is saved automatically to localStorage. Your completed lessons persist across sessions. The progress bar in the sidebar shows how far through the curriculum you are. Completing every lesson in a chapter triggers a confetti animation. You can reset progress from any lesson forward using the Mark Done button toggle.

The AJAX chapter (seven lessons) covers $.get(), $.post(), $.ajax(), $.getJSON(), .load(), $.ajaxSetup(), and global AJAX events. All live examples use JSONPlaceholder — a free public REST API — so the AJAX calls work immediately without needing a backend.

The Utilities chapter introduces five helper functions that every jQuery developer encounters: $.each() for iterating arrays and objects, $.map() for transforming collections, $.grep() for filtering arrays, $.extend() for merging options objects, and $.type() for reliable type detection that handles null and arrays correctly unlike typeof.

The Deferred & Promises chapter covers jQuery's async programming model: creating a $.Deferred(), resolving and rejecting it, attaching .done(), .fail(), and .always() handlers, coordinating parallel operations with $.when(), and chaining sequential async steps with .then(). These patterns underpin jQuery's AJAX methods and appear throughout older codebases.

The Plugin Basics chapter teaches you to extend jQuery itself. You will write a plugin using the $.fn pattern, wrap it in an IIFE to protect the $ alias, return this to keep chains alive, and add a method-dispatch pattern with per-element state stored via $.data(). The quick-check challenges appear on 13 of the 72 lessons and test your understanding of the method just covered.