Chrome extension simple script not being injected

Question

I\'m trying my first steps in writing a minimal Chrome extension, and I cannot figure out why it does not execute my clientScript.js.

This is my manifest.json:

Answer 1

Assuming you did reload the tab (the content scripts are injected only on initial tab load, see this for more info and a workaround), you're probably a victim of the infamous Google's decision to hide www in the address bar: if you enter the edit mode and select/copy the entire text (or simply double-click the address) you will see the site's URL is actually https://www.twitch.tv/ so your manifest.json has an incorrect URL pattern that doesn't match the real site.

Simply use a generalized pattern like "https://*.twitch.tv/*" that will match both https://www.twitch.tv/ and https://twitch.tv/ and any other subdomain(s).

P.S. as a debugging step, you can check if the content script is even injected by looking at the context selector in devtools console toolbar or in devtools -> Sources -> Content scripts panel. And if you want to restore the classic address bar behavior, see https://superuser.com/a/1498561