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alarms.onAlarm

files/en-us/mozilla/add-ons/webextensions/api/alarms/onalarm/index.md

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Fired when any alarm set by the extension goes off.

Syntax

js-nolint
browser.alarms.onAlarm.addListener(listener)
browser.alarms.onAlarm.removeListener(listener)
browser.alarms.onAlarm.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 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:
      • alarm
        • : {{WebExtAPIRef('alarms.Alarm')}}. The alarm that fired. Use Alarm.name to figure out which alarm fired.

Examples

Handle an alarm going off:

js
function handleAlarm(alarmInfo) {
  console.log(`on alarm: ${alarmInfo.name}`);
}

browser.alarms.onAlarm.addListener(handleAlarm);

{{WebExtExamples}}

Browser compatibility

{{Compat}}

[!NOTE] This API is based on Chromium's chrome.alarms API.