extension - Mozilla

Types

extension.lastError Deprecated: Set for the lifetime of a callback if an asynchronous extension API has resulted in an error. If no error has occurred, lastError will be undefined.
extension.inIncognitoContext: True for content scripts running inside incognito tabs, and for extension pages running inside an incognito process. (The latter only applies to extensions with "incognito": "split" set in their manifest.json file.)

extension.getBackgroundPage(): Returns the Window object for the background page running inside the current extension. Returns null if the extension has no background page.
extension.getExtensionTabs() Deprecated: Returns an array of the JavaScript Window objects for each of the tabs running inside the current extension.
extension.getURL() Deprecated: Converts a relative path within an extension install directory to a fully-qualified URL.
extension.getViews(): Returns an array of the Window objects for each of the pages running inside the current extension.
extension.isAllowedIncognitoAccess(): Retrieves the state of the extension's access to Incognito-mode (as determined by the user-controlled 'Allowed in Incognito' checkbox).
extension.isAllowedFileSchemeAccess(): Retrieves the state of the extension's access to the file:// scheme (as determined by the user-controlled 'Allow access to File URLs' checkbox).
extension.sendRequest() Deprecated: Sends a single request to other listeners within the extension.
extension.setUpdateUrlData(): Sets the value of the ap CGI parameter used in the extension's update URL. This value is ignored for extensions that are hosted in the browser vendor's store.

extension.onRequest Deprecated: Fired when a request is sent from either an extension process or a content script.
extension.onRequestExternal Deprecated: Fired when a request is sent from another extension.

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

This page was last modified on ⁨Jul 17, 2025⁩ by MDN contributors.