What about setTimeout(obj.method, 1)?
(Spoilers: this == window, not what is left of the function call)
You are not calling the function, you are passing a reference to setTimeout that calls it directly, without the obj. before the call.
@getify explains it flawlessly, there are 4 modes: new, obj., bind/apply/call and default (window or error in strict mode)
As nhpatt notes you're not actually calling obj.method here, you're passing it as an argument, which will be called at a later time.
Looking at a possible implementation of setTimeout makes it clearer:
function setTimeout(func, delay) {
// wait for the delay to complete..
func();
}
If you're doing a direct function call like myFunc() there is nothing "left" of the function call. But you might think of it as actually doing window.myFunc(), which again explains why this === window. In strict mode this behavior has been "fixed" so that this === undefined.
It's all about how a function is called.