JavaScript objects

Question

What are the differences between these two codes in JavaScript?

var obj = new Object();
obj.X = 10;
obj.Y = 20;

And,

var obj = {X:10, Y:20};

Answer 1

The second is a shortcut for the first. Functionally they are the same.

Answer 2

Nothing really. Well, that's not quite true, but the differences are far too minor to mention.

Answer 3

Nothing at all. Just syntax.

You could also use:

var obj = new Object();
obj["X"] = 10;
obj["Y"] = 20;

Answer 4

Object literal format {} was introduced with JavaScript 1.2, along with Array literal format [].

So the more readable variant {X:10, Y:20} won't work in Netscape 3! (Oh no!)