Book excerpt: The essential JavaScript resource—fully updated Design, debug, and publish high-performance web pages and applications using tested techniques and best practices from expert developers. The all-new edition of this comprehensive guide has been thoroughly revised and expanded to cover the latest JavaScript features, tools, and programming methods. JavaScript: The Complete Reference, Third Edition provides illustrative examples, line-by-line code samples, and practical development advice—from the core of the language to the various standard and emerging APIs supported by modern web browsers. This in-depth resource covers everything you need to know, whether you’re trying to understand the fundamentals of weak typing in JavaScript, reduce your confusion over closures, or perform common tasks like form validation or Ajax calls. Explore core JavaScript syntax and data types Investigate often confusing concepts such as weak typing and closures Use object-oriented programming the JavaScript way See what changes come from ECMAScript 5 Perform dynamic content updates using DOM methods Handle user-generated events with modern event models Modernize form handling with HTML5 and JavaScript Use the XMLHttpRequest object to create Ajax applications Control animation and multimedia content with JavaScript Generate bitmap graphics with the Canvas API Learn methods to handle the challenges of cross-browser coding Discover defensive development and error handling