The URL is a location property and the location object applies to the

[adakist]

The URL is a location property and the location object applies to the document object.

[brumbino]

Thus, the location is a property of the document, and not the window. href is a property of the location object, which in turn is a property of the document object, which in turn is a property of the window object. You must write down a sequence of objects, starting with the top level object that is the window object and work your way down to the lower-level object whose property you want to access.