How this landing page opens a backunder just on scroll or touch?

Hey guys

I’ve uploaded a small screen recording of a landing page that I found really interesting.

In that page, whenever a user just scrolls, touches the screen, or clicks anywhere - it automatically opens a new clickunder tab with another landing page.

I want to understand how they’re doing this.

• Is it some kind of JavaScript trick or custom code?
• How are they triggering a clickunder even on just scroll or touch?
• And how can I set up something similar for my own landing pages or smartlink offers?

If anyone has done this before or knows the logic behind it, please share a bit of info.
Would really appreciate your help

( Note- I already have backunder code given by Luke, I am asking how this landing page open a back tab just by user's finger scroll or little touch anywhere on screen