chrome.userScripts

Description

Use the userScripts API to execute user scripts in the User Scripts context.

Permissions

userScripts

To use the User Scripts API, chrome.userScripts, add the "userScripts" permission to your manifest.json and "host_permissions" for sites you want to run scripts on.

{
  "name": "User script test extension",
  "manifest_version": 3,
  "minimum_chrome_version": "120",
  "permissions": [
    "userScripts"
  ],
  "host_permissions": [
    "*://example.com/*"
  ]
}

Availability

Chrome 120+ MV3+

Concepts and usage

A user script is a snippet of code injected into a web page to modify its appearance or behavior. Unlike other extension features, such as Content Scripts and the chrome.scripting API, the User Scripts API lets you run arbitrary code. This API is required for extensions that run scripts provided by the user that cannot be shipped as part of your extension package.

Developer mode for extension users

As an extension developer, you already have Developer mode enabled in your installation of Chrome. For user script extensions, your users will also need to enable developer mode. Here are instructions that you can copy and paste into your own documentation.

  1. Go to the Extensions page by entering chrome://extensions in a new tab. (By design chrome:// URLs are not linkable.)

  2. Enable Developer Mode by clicking the toggle switch next to Developer mode.