Javascript object constructor vs object literal [duplicate]

Question

Possible Duplicate:
creating objects - new object or object literal notation?
Literal notation VS. constructor to create objects in JavaScript

I'm going through my very first Javascript tutorial.

I just found two ways to create a JS object.

var person = new Object();
person.name = "Tom";
person.age = "17";

and

var person = {};
person.name = "Tom";
person.name = "17"

Any difference between these two ways of object creation? Since the second looks simpler, can we always use it under any condition?

Answer 1

Not only is the second syntax easier to read and not only will it work under any condition, but the first syntax might not work under all conditions:

function Object() {
    // Oh crap, we have redefined Object!
    return [];    // return an array because we are EVIL
}

var person = new Object();   // not what we think it is

But {}, being a syntactic construct, is immune to such evil trickery.

In addition, the object literal notation can be partially optimized at parse time, since after all there's only one object type that could be created. That may result in a minuscule performance increase.