A funny prank

There has a simple question and two direct anwsers. All remaining things are up to you :))

Website

Access https://vuongsg.github.io/funny-prank/ for playing with it.

Technologies

HTML
CSS
Vanilla JavaScript

Browsers support

Edge 16+
Firefox 52+
Chrome 57+
Safari 10.1+
Opera 44+
Safari on IOS 10.3+
Android Browser 90+
Opera Mobile 62+
Chrome for Android 90+
Firefox for Android 87+