So why would you want to buy this version if you already bought the first? Quite simply, because a lot has changed since the first book came out. You should buy this book if you want to learn:
- ECMAScript 4 and its successor, ECMAScript 3.1.
- Best practices for development, performance, coding style, maintainability, and deployment.
- Cross-domain Ajax requests in Internet Explorer and Firefox.
- The latest features of HTML 5 and which parts have already been implemented.
Disclaimer: Any viewpoints and opinions expressed in this article are those of Nicholas C. Zakas and do not, in any way, reflect those of my employer, my colleagues, Wrox Publishing, O'Reilly Publishing, or anyone else. I speak only for myself, not for them.