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.