How app can control on notification via webview component

Basically, I had made a website of music and now for quick access I use mit app inventor's webview.
Now I want the app to work in Background, now it is working tough but I am unable to control song like switching songs, play/pause...
So I want like from outside the app, I can easily control the songs just like sportify.
The crome and other browser support notification so I can change the songs even the website is not open.
So how can I enable the notification for webview?

Are you using a background (foreground) service extension or other method to run your app in "the background". If so show your relevant blocks.

Have you attempted controlling the website from your app without sending it to the background ?