extension

Utilities related to your add-on. Get URLs to resources packages with your add-on, get the Window object for your add-on's pages, get the values for various settings. Note that 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 ansychronous extension api has resulted in an error. If no error has occured 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.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.getBackgroundPage(): Returns the Window object for the background page running inside the current extension. Returns null if the extension has no background page.
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.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.

	Edge	Firefox	Chrome	Opera
`ViewType`	?	45.0	Yes	33
`getBackgroundPage`	?	45.0	Yes	33
`getExtensionTabs`	?	No	Yes	No
`getURL`	?	45.0	Yes	33
`getViews`	?	45.0	Yes	33
`inIncognitoContext`	?	45.0	Yes	33
`isAllowedFileSchemeAccess`	?	No	Yes	33
`isAllowedIncognitoAccess`	?	48.0	Yes	33
`lastError`	?	47.0	Yes	33
`onRequest`	?	No	Yes	33
`onRequestExternal`	?	No	Yes	33
`sendRequest`	?	No	Yes	No
`setUpdateUrlData`	?	No	Yes	33

	Firefox
`ViewType`	48.0
`getBackgroundPage`	48.0
`getExtensionTabs`	No
`getURL`	48.0
`getViews`	48.0
`inIncognitoContext`	48.0
`isAllowedFileSchemeAccess`	No
`isAllowedIncognitoAccess`	48.0
`lastError`	48.0
`onRequest`	No
`onRequestExternal`	No
`sendRequest`	No
`setUpdateUrlData`	No

Chrome incompatibilities

Firefox does not support:
- isAllowedIncognitoAccess()
- isAllowedFileSchemeAccess()
- setUpdateUrlData()
- onRequest
- onRequestExternal
- getExtensionTabs()
- sendRequest()

Example add-ons

Acknowledgements

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

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