This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
FocusEvent.relatedTarget read-only property represents a secondary target for this event, which will depend on the event itself. In some cases (like when tabbing in or out of a page), this property may be set to
null for security reasons.
secondTarget = focusEvent.relatedTarget
|Document Object Model (DOM) Level 3 Events Specification
The definition of 'FocusEvent.relatedTarget' in that specification.
|Working Draft||Initial definition.|
|Feature||Chrome||Edge||Firefox (Gecko)||Internet Explorer||Opera||Safari|
|Basic support||(Yes)||(Yes)||48.0 (48.0)||9.0||(Yes)||(Yes)|
|Feature||Android||Edge||Firefox Mobile (Gecko)||IE Mobile||Opera Mobile||Safari Mobile|
|Basic support||(Yes)||(Yes)||24.0 (24.0)||(Yes)||(Yes)||(Yes)|
FocusEventinterface it belongs to.