Beforeunload event is not working on mobile phone

Question

I am using an beforeunload event, to notify user if he changed form without saving it, before closing the browser. I am using it in Angular

Code exmaple:

  @HostListener('window:beforeunload', ['$event'])
  unloadNotification($event: BeforeUnloadEvent) {
    if (!this.hasFormChanged) return;
    $event.returnValue();
  }

It works fine on PC/laptop, but doesn't work on mobile.

However, here it says that it doesn't work on mobile: https://developer.mozilla.org/en-US/docs/Web/API/Window/beforeunload_event

I am a little bit lost with an alternative.. Do you have any suggestions?

Thanks to everyone for help.