How to add scroll event in code playground?

Question

https://code.sololearn.com/W6Sx7RrUvBnH/#html

Edited:
Hm... Origin code don't work in Firefox and in mobile app. But in Chrome it's ok.
Why this don't work in Firefox?

Answer 1

The bare minimum that gets this working is:
13: width: 100%; // of the containing element, from 100vw (of the view)
14: height: 100%; // ... from 100vh

134: window.onscroll=scroll; // addEventListener hasn't always worked for me

I'm not saying this is right, only that it works for me.

Answer 2

by using <marquee> </marquee> tags