windows.onFocusChanged

Syntax

browser.windows.onFocusChanged.addListener(listener)
browser.windows.onFocusChanged.removeListener(listener)
browser.windows.onFocusChanged.hasListener(listener)

Events have three functions:

addListener(listener)

Adds a listener to this event.

removeListener(listener)

Stop listening to this event. The listener argument is the listener to remove.

hasListener(listener)

Check whether a listener is registered for this event. Returns true if it is listening, false otherwise.

addListener syntax

Parameters

listener

The function called when this event occurs. The function is passed this argument:

windowId

integer. ID of the newly focused window.

Examples

Log focus changes:

browser.windows.onFocusChanged.addListener((windowId) => {
  console.log(`Newly focused window: ${windowId}`);
});

Example extensions

• bookmark-it

Browser compatibility