FocusEvent: relatedTarget property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨July 2015⁩.

The relatedTarget read-only property of the FocusEvent interface 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.