windows.onFocusChanged

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

Note: On some Linux window managers, WINDOW_ID_NONE will always be sent immediately preceding a switch from one browser window to another.

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

Chrome Edge Firefox Firefox for Android Opera
Basic support Yes Yes 45.0 No 33

Examples

Log focus changes:

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

Acknowledgements

This API is based on Chromium's chrome.windows API. This documentation is derived from windows.json in the Chromium code.

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.

Document Tags and Contributors

 Contributors to this page: wbamberg, Makyen, chrisdavidmills
 Last updated by: wbamberg,