windows.onFocusChanged
Fired when the currently focused window changes. Will be windows.WINDOW_ID_NONE
if all browser windows have lost focus.
Note: In Windows and some Linux window managers, WINDOW_ID_NONE will always be sent immediately preceding a switch from one browser window to another.
Syntax
js
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. Returnstrue
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.
Browser compatibility
BCD tables only load in the browser
Examples
Log focus changes:
js
browser.windows.onFocusChanged.addListener((windowId) => {
console.log(`Newly focused window: ${windowId}`);
});
Example extensions
Note: This API is based on Chromium's chrome.windows
API. This documentation is derived from windows.json
in the Chromium code.