#import // https://www.w3.org/TR/uievents/#idl-focusevent [Exposed=Window] interface FocusEvent : UIEvent { constructor(DOMString type, optional FocusEventInit eventInitDict = {}); readonly attribute EventTarget? relatedTarget; }; // https://www.w3.org/TR/uievents/#idl-focuseventinit dictionary FocusEventInit : UIEventInit { EventTarget? relatedTarget = null; };