ECMAScript 5 released

This is a good summary of the delta.

However, the article author didn't really explain why strict mode is interesting. One of the core requirements of ECMAScript 3.1 (now 5) was to make the language more secure.

For example, in strict mode you can't declare new variables which are eval'd. This makes it harder to XSS. As does the reservation of eval (so it can't be overridden) and the denial of access to the global object.

This is really important because using strict will not only make your JavaScript better (more like "The Good Parts") but also more performant (less global scope) and more secure.

Does anyone know what the browsers' plans are for implementing this? Hopefully the next major version of Chrome, FF, and IE have it (properly) implemented. Until then, it is hard to get excited as it will likely be quite awhile before it's ubiquitous.

Ok, can anyone smarter than myself tell me if I'm justified in getting a little bit excited about the 'freeze' function on objects that makes properties read only? My first thought is that it sounds like a perfect first line of defence in terms of being able to get trustworthy data back from the client bundled up in a frozen object.

Oooh neat. Maybe I should claim that the parts of the ES3.1 standard I didn't implement were actually presaging ES5. Neat.

Finally! Javascript gets an "Option Explicit" ala "use strict;"