Firefox 64 for developers

Questo articolo fornisce informazioni riguardo i cambiamenti in Firefox 64 che interesseranno gli sviluppatori. Firefox 64 è stato rilasciato l' 11 Dicembre, 2018.

Changes for web developers

Developer tools



No changes.




No changes.




Service workers

Media, Web Audio, and WebRTC


  • The Window.event (en-US) property, added in Firefox 63 to aid with web compat issues, has been put behind a pref (dom.window.event.enabled) and disabled by default in release versions for now due to other issues that have been uncovered (bug 1493869). Note that this was actually done late in the Firefox 63 release cycle, but we are mentioning it here just in case.
  • The LocalMediaStream (en-US) interface and its stop() method have been removed (bug 1258143). This method is no longer available with the deprecation of LocalMediaStream. See Stopping a video stream in MediaStreamTrack.stop() to learn how to stop an entire stream.
  • The AudioStreamTrack and VideoStreamTrack interfaces have been removed, as both have been deprecated for some time (bug 1377146). Their functionality has been merged into MediaStreamTrack (en-US); tracks are now identified by the value of their kind (en-US) property, such as audio or video.



No changes.

Changes for add-on developers

API changes

  • A new API, browser.menus.overrideContext(), can be called from the contextmenu DOM event to set a custom context menu in extension pages. This API allows extensions to hide all default Firefox menu items in favor of providing a custom context menu UI. This context menu can consist of multiple top-level menu items from the extension, and may optionally include tab or bookmark context menu items from other extensions. See this blog post for more details.
    • browser.menus.overrideContext() was implemented in (bug 1280347).
    • The showDefaults: false option, which can be used to hide the default context menu options, was implemented in (bug 1367160).
  • You can now restrict where context menus can appear in an add-on using the new viewTypes property in menus.create() (en-US) and menus.update() (en-US) (bug 1416839).
  • menus.update() (en-US) can now be used to update the icon of an existing menu item (bug 1414566).
  • Extensions can now detect which mouse button was used when a menu item was clicked — this can be found using the new button property of menus.OnClickData (en-US) (bug 1469148).


  • The windows.create() (en-US) method now has a new option available — cookieStoreId — which specifies the CookieStoreId to use for all tabs that were created when the window is opened (bug 1393570).


  • The privacy.websites (en-US) cookieConfig property is an object that can accept a behavior property — this property can now take a new value, reject_trackers, which instructs the extension to reject tracking cookies (bug 1493057).

devtools.panels API

Manifest changes

  • The new pinned property of the page_action manifest key enables extensions to control whether their page actions should be pinned to the location bar on install or not (bug 1494135).
  • In native manifests on Windows, the 32-bit registry view (Wow6432Node) will be checked first for registry keys, followed by the "native" registry view; you should use whichever is appropriate for your application (bug 1494709).
  • The chrome_settings_overrides field's search_provider object can now include new properties — suggest_url and suggest_url_post_params (bug 1486819), and search_url_post_params.

See also

Older versions