Question

Why does JQuery ( latest source ) tie there Ajax Request Object to a window like this?

    return new window.XMLHttpRequest();

I’m asking b.c. in my source I don’t do this.

I just do

return new XMLHttpRequest();

Answer 1

Because the XMLHttpRequest object is a child of the window object.

You can reference it as a lone object since window is the parent scope in the browser; i.e. the global scope. If the reference isn’t in the local scope (closure), JavaScript keeps going up the scope chain until the reference found. Using window.XMLHttpObject prevents all the look ups by telling the browser exactly where to find it.