[Global=Window, Exposed=Window]
interface Window {
};

[TreatNonObjectAsNull]
callback EventHandlerNonNull = any (Event event);
typedef EventHandlerNonNull? EventHandler;

[NoInterfaceObject]
interface GlobalEventHandlers {
};
Window implements GlobalEventHandlers;

interface Navigator {
};

interface Element {
};

interface HTMLElement : Element {
};
HTMLElement implements GlobalEventHandlers;

interface Document {
};
Document implements GlobalEventHandlers;

interface MouseEvent {
};