windows.onFocusChanged

Fired when the currently focused window changes. Will be windows.WINDOW_ID_NONE if all browser windows have lost focus.

Syntax

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

Events have three functions:

addListener(callback)

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

callback

Function that will be called when this event occurs. The function will be passed the following arguments:

windowId

integer. ID of the newly focused window.

Browser compatibility

Examples

Log focus changes:

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

Example extensions

• bookmark-it