How can I call a Ionic 2 method from an external JS file (web site)?

Hi, I have an app in Ionic2, and I have a method in my login.ts for to close the app, like this:

closeApp(){ this.platform.exitApp(); }

But I want to execut this method from another method in a JS file in my website (outside my app), I mean, I want to close the app from my website. Any idea?

+1
Same problem. Do you solve?

I cannot conceive of how this would be possible.