The FocusEvent.relatedTarget read-only property is the secondary target, depending on the type of event:
| Event name | target |
relatedTarget |
|---|---|---|
blur |
The EventTarget losing focus |
The EventTarget receiving focus (if any). |
focus |
The EventTarget receiving focus |
The EventTarget losing focus (if any) |
focusin |
The EventTarget receiving focus |
The EventTarget losing focus (if any) |
focusout |
The EventTarget losing focus |
The EventTarget receiving focus (if any) |
Note that many elements can't have focus, which is a common reason for relatedTarget to be null. relatedTarget may also be set to null for security reasons, like when tabbing in or out of a page.
MouseEvent.relatedTarget is a similar property for mouse events.