The sixth edition of the bestseller “JavaScript. The Definitive Guide has been completely revised and updated with JavaScript information to keep up with the state of the art in Web 2.O application development. This book is both a programmer's guide with a large number of practical examples, and a comprehensive reference for the basic JavaScript language and client application interfaces provided by web browsers. The publication covers the ECMAScript 5 and HTML5 standards. Many chapters have been rewritten, others have been updated with new information, and there are new chapters covering the jQuery library and server-side JavaScript support. Part I introduces the basics of JavaScript. Part II describes the scripting environment provided by web browsers. The focus is on script development using unobtrusive JavaScript techniques and the DOM. Part III is an extensive reference to the core JavaScript language, including descriptions of all classes, objects, constructors, methods, functions, properties and constants defined in JavaScript 1.8, V8 3.0 and ECMAScript 5. Part IV is a reference to client-side JavaScript. It describes the web browser API, the DOM API Level 3 standard, and the WebSockets and Web Workers technologies recently included in the HTML5 standard, localStorage and sessionStorage objects, as well as the "audio" and "video" tags. The publication is recommended for programmers who need to learn a programming language for Web, as well as programmers who use JavaScript and want to master it perfectly.