The window object represents the open window in the browser. So every tab and every open browser is a window object.
The location object contains information about the current URL. The location object is part of the window object and is accessed through the window.location property.
The screen object retuns information about the client side screen. Such as size, type, resolution ect.
The history object is what is used for the back and forward button in the browser. This also keeps track of where you have been and what you have been looking at.
the document object is displayed in the window object and renders into the browser displaying the webpage that is made out of Html and css