Difference Between window and document.defaultView?

I’m working with getComputedStyle, and realized that I’ve, at various times, used both of the following:

return window.getComputedStyle(elem, null);
return document.defaultView.getComputedStyle(elem, null);

Is there any difference between the two? Even in edge cases, like frames, XML, etc.

Bonus Question: If we can just use the “window.getComputedStyle” syntax, then couldn’t we also just use “getComputedStyle”?


/* firefox returned value: (Boolean)