index.md

---

title: events.Event
slug: Mozilla/Add-ons/WebExtensions/API/events/Event
page-type: webextension-api-type
tags:
  - API
  - Add-ons
  - Event
  - Extensions
  - Non-standard
  - Reference
  - Type
  - WebExtensions
  - events
browser-compat: webextensions.api.events.Event

---

{{AddonSidebar()}}

An object which allows the addition and removal of listeners for a browser event.

Type

Values of this type are objects.

Methods

• {{WebExtAPIRef("events.Event.addListener","events.Event.addListener()")}}

  • : Registers an event listener callback to an event.

• {{WebExtAPIRef("events.Event.removeListener","events.Event.removeListener()")}}

  • : Deregisters an event listener callback from an event.

• {{WebExtAPIRef("events.Event.hasListener","events.Event.hasListener()")}}

  • : Tests registration status of a listener.

• {{WebExtAPIRef("events.Event.hasListeners","events.Event.hasListeners()")}}

  • : Tests whether any listeners are registered to the event.

• {{WebExtAPIRef("events.Event.addRules","events.Event.addRules()")}}

  • : Registers rules to handle events.

• {{WebExtAPIRef("events.Event.getRules","events.Event.getRules()")}}

  • : Returns currently registered rules.

• {{WebExtAPIRef("events.Event.removeRules","events.Event.removeRules()")}}

  • : Unregisters currently registered rules.

Browser compatibility

{{Compat}}

{{WebExtExamples}}

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