How to get my extension's id from JavaScript?

Question

I\'m writing a Chrome extension, I need to get my extension\'s id in my code, so I don\'t need to change it manually every time. How can I do this?

Answer 1

In WebExtensions, you have two options:

1. chrome.runtime.id
2. chrome.i18n.getMessage("@@extension_id")

In Chrome and Opera, they will return the same value, but in Firefox there is a difference.

In Firefox, chrome.runtime.id will return the so called "Extension ID", but chrome.i18n.getMessage("@@extension_id") will return the "Internal UUID". The extension ID is the same for all users, but the internal UUID is created when the extension is installed and is unique per user.

Depending on the context, the extension ID will not be what you want. For example, Firefox uses the internal UUID to fill the origin header, not the extension ID.

Example 1: Ghostery in Firefox 61

chrome.runtime.id                        --> "firefox@ghostery.com"
chrome.i18n.getMessage("@@extension_id") --> "e3225586-81a0-47c3-8612-d95fb0c2a609"

For fetch requests from within the extension, Firefox will add the header

origin: moz-extension://e3225586-81a0-47c3-8612-d95fb0c2a609

Example 2: Ghostery in Chrome

chrome.runtime.id                        --> "mlomiejdfkolichcflejclcbmpeaniij"
chrome.i18n.getMessage("@@extension_id") --> "mlomiejdfkolichcflejclcbmpeaniij" 

For fetch requests from within the extension, Chrome will add the header

origin: chrome-extension://mlomiejdfkolichcflejclcbmpeaniij