index.md

---

title: extension.getBackgroundPage()
slug: Mozilla/Add-ons/WebExtensions/API/extension/getBackgroundPage
page-type: webextension-api-function
tags:
  - API
  - Add-ons
  - Extension
  - Extensions
  - Method
  - Non-standard
  - Reference
  - WebExtensions
  - getBackgroundPage
browser-compat: webextensions.api.extension.getBackgroundPage

---

{{AddonSidebar()}}

Returns the Window of the background page if the background script is running. If the script is not running, null is returned.

This a synchronous function.

Note: This method cannot be used in Private Browsing mode — it always returns null. Consider using {{WebExtAPIRef("runtime.sendMessage","runtime.sendMessage()")}} or {{WebExtAPIRef("runtime.connect","runtime.connect()")}}. See Firefox bug 1329304 for more information.

Syntax

let page = browser.extension.getBackgroundPage()

Parameters

None.

Return value

object. Window of the background page or null.

Examples

Suppose a background script defines a function foo():

// background.js

function foo() {
  console.log("I'm defined in background.js");
}

A script running in a popup can call this function directly like this:

// popup.js

let page = browser.extension.getBackgroundPage();
page.foo(); // -> "I'm defined in background.js"

{{WebExtExamples}}

Browser compatibility

{{Compat}}

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