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extension

Utilities related to your extension. Get URLs to resources packages with your extension. Get the Window object for your extension's pages. Get the values for various settings.

Note: The messaging APIs in this module are deprecated in favor of the equivalent APIs in the runtime module.

Types

extension.ViewType: The type of extension view.

Properties

extension.lastError: 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 'split' incognito_behavior.)

Functions

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(): Returns an array of the JavaScript Window objects for each of the tabs running inside the current extension.
extension.getURL(): 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(): 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.

Events

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

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`ViewType`	Yes	79	45	?	Yes	14	?	?	48	?	?	?
`getBackgroundPage`	Yes	14	45	?	Yes	14	?	?	48	?	?	?
`getExtensionTabs`	Yes	79	No	?	No	No	?	?	No	?	?	?
`getURL`	Yes	14	45	?	Yes	14	?	?	48	?	?	?
`getViews`	Yes	14	45 If this is called from a page that is part of a private browsing window, such as a sidebar in a private window or a popup opened from a private window, then its return value will not include the extension's background page.	?	Yes	14	?	?	48 If this is called from a page that is part of a private browsing window, such as a sidebar in a private window or a popup opened from a private window, then its return value will not include the extension's background page.	?	?	?
`inIncognitoContext`	Yes	17	45	?	Yes	14 Always returns false.	?	?	48	?	?	?
`isAllowedFileSchemeAccess`	Yes	79	48	?	Yes	14 Always returns false.	?	?	48	?	?	?
`isAllowedIncognitoAccess`	Yes	17	48	?	Yes	14 Always returns true.	?	?	48	?	?	?
`lastError`	Yes	79	47	?	Yes	No	?	?	48	?	?	?
`onRequest`	Yes	79	No	?	Yes	No	?	?	No	?	?	?
`onRequestExternal`	Yes	79	No	?	Yes	No	?	?	No	?	?	?
`sendRequest`	Yes	79	No	?	No	No	?	?	No	?	?	?
`setUpdateUrlData`	Yes	79	No	?	Yes	No	?	?	No	?	?	?

Example extensions

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

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.

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https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/extension