I just started thinking about this, but couldn't get any differences to expose themselves whilst mucking around in [jsFiddle](http://jsfiddle.net/L9Tm3/).

```
var a = new Array(1),
    b = Array(1);

console.log(a, b);

```

Output is two arrays with one undefined member.

Doing a `for ( in )` reveals they have the same properties.

What are the differences between these? Does the first one simply instantiate the object explicitly?

Please don't lecture me about using array literal notation as I already know about that. I'm more wishing to fill this gap in my knowledge explained above.