chrome.extension

Description:	The `chrome.extension` API has utilities that can be used by any extension page. It includes support for exchanging messages between an extension and its content scripts or between extensions, as described in detail in Message Passing.
Availability:	Stable since Chrome 5.

Support for content scripts

Unlike the other chrome.* APIs, parts of chrome.extension can be used by content scripts:

runtime.sendMessage and runtime.onMessage: Simple communication with extension pages
runtime.connect and runtime.onConnect: Extended communication with extension pages
extension.getURL: Access to extension resources such as image files

For details, see Content Scripts.

Summary

Properties
lastError
inIncognitoContext
Methods
sendRequest − `chrome.extension.sendRequest(string extensionId, any request, function responseCallback)`
getURL − `string chrome.extension.getURL(string path)`
getViews − `array of Window chrome.extension.getViews(object fetchProperties)`
getBackgroundPage − `Window chrome.extension.getBackgroundPage()`
getExtensionTabs − `array of Window chrome.extension.getExtensionTabs(integer windowId)`
isAllowedIncognitoAccess − `chrome.extension.isAllowedIncognitoAccess(function callback)`
isAllowedFileSchemeAccess − `chrome.extension.isAllowedFileSchemeAccess(function callback)`
setUpdateUrlData − `chrome.extension.setUpdateUrlData(string data)`
Events
onRequest
onRequestExternal

Properties

object

chrome.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.

Properties
string	message	Description of the error that has taken place.

boolean chrome.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.

Methods

sendRequest

sendRequest is deprecated. Please use runtime.sendMessage.


              chrome.extension.sendRequest(string extensionId, any request, function responseCallback)

Sends a single request to other listeners within the extension. Similar to runtime.connect, but only sends a single request with an optional response. The extension.onRequest event is fired in each page of the extension.

Parameters

string (optional) extensionId The extension ID of the extension you want to connect to. If omitted, default is your own extension.

any request

function

(optional) responseCallback

If you specify the responseCallback parameter, it should be a function that looks like this:

function(any response) {...};

any

response

The JSON response object sent by the handler of the request. If an error occurs while connecting to the extension, the callback will be called with no arguments and runtime.lastError will be set to the error message.

getURL


              string
              chrome.extension.getURL(string path)

Converts a relative path within an extension install directory to a fully-qualified URL.

Parameters
string	path	A path to a resource within an extension expressed relative to its install directory.

getViews


              array of Window
              chrome.extension.getViews(object fetchProperties)

Returns an array of the JavaScript 'window' objects for each of the pages running inside the current extension.

Parameters

object

(optional) fetchProperties

enum of `"tab"`, `"infobar"`, `"notification"`, or `"popup"`	(optional) type	The type of view to get. If omitted, returns all views (including background pages and tabs). Valid values: 'tab', 'infobar', 'notification', 'popup'.
integer	(optional) windowId	The window to restrict the search to. If omitted, returns all views.

getBackgroundPage


              Window
              chrome.extension.getBackgroundPage()

Returns the JavaScript 'window' object for the background page running inside the current extension. Returns null if the extension has no background page.

Returns

getExtensionTabs

getExtensionTabs is deprecated. Please use extension.getViews {type: "tab"}.


              array of Window
              chrome.extension.getExtensionTabs(integer windowId)

Returns an array of the JavaScript 'window' objects for each of the tabs running inside the current extension. If windowId is specified, returns only the 'window' objects of tabs attached to the specified window.

Parameters
integer	(optional) windowId

isAllowedIncognitoAccess


              chrome.extension.isAllowedIncognitoAccess(function callback)

Retrieves the state of the extension's access to Incognito-mode (as determined by the user-controlled 'Allowed in Incognito' checkbox.

Parameters

function

callback

The callback parameter should be a function that looks like this:

function(boolean isAllowedAccess) {...};

boolean

isAllowedAccess

True if the extension has access to Incognito mode, false otherwise.

isAllowedFileSchemeAccess


              chrome.extension.isAllowedFileSchemeAccess(function callback)

Retrieves the state of the extension's access to the 'file://' scheme (as determined by the user-controlled 'Allow access to File URLs' checkbox.

Parameters

function

callback

The callback parameter should be a function that looks like this:

function(boolean isAllowedAccess) {...};

boolean

isAllowedAccess

True if the extension can access the 'file://' scheme, false otherwise.

setUpdateUrlData


              chrome.extension.setUpdateUrlData(string data)

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 Chrome Extension Gallery.

Parameters
string	data

Events

onRequest

onRequest is deprecated. Please use runtime.onMessage.

Fired when a request is sent from either an extension process or a content script.

addListener


                    chrome.extension.onRequest.addListener(function callback)

Parameters

function

callback

The callback parameter should be a function that looks like this:

function(any request, runtime.MessageSender sender, function sendResponse) {...};

any	(optional) request	The request sent by the calling script.
runtime.MessageSender	sender
function	sendResponse	Function to call (at most once) when you have a response. The argument should be any JSON-ifiable object, or undefined if there is no response. If you have more than one `onRequest` listener in the same document, then only one may send a response.

onRequestExternal

onRequestExternal is deprecated. Please use runtime.onMessageExternal.

Fired when a request is sent from another extension.

addListener


                    chrome.extension.onRequestExternal.addListener(function callback)

Parameters

function

callback

The callback parameter should be a function that looks like this:

function(any request, runtime.MessageSender sender, function sendResponse) {...};

any	(optional) request	The request sent by the calling script.
runtime.MessageSender	sender
function	sendResponse	Function to call when you have a response. The argument should be any JSON-ifiable object, or undefined if there is no response.