What's New in ECMAScript 5

This piece details the new parts in ECMAScript 5 that will be implemented by Chakra (Internet Explorer 9), SpiderMonkey (Firefox), SquirrelFish (Safari), V8 (Chrome), and Carakan (Opera) and other new generation JavaScript engines in 2011.

Strict mode is at the core. It not only makes your programs simpler and less error prone but also easier for a JavaScript engine with just-in-time compilation (JIT), such as those listed above, to optimize.

That is to say, run faster. Moreover, coding in strict mode, which is totally backward compatible, prepares you for ECMAScript 6, which will require doing so.

It also explores a number of new OOP features provided by ECMAScript 5, as well as new iteration methods, JSON handling, and binding and currying.