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extension.getBackgroundPage()

files/en-us/mozilla/add-ons/webextensions/api/extension/getbackgroundpage/index.md

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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

js-nolint
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():

js
// 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:

js
// 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.

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