How can I change background image when user scrolls on the div?

Question

How can I change background image when the user scrolls on the div called step2?

https://code.sololearn.com/WIEM419wsuDr

Answer 1

Check this
https://www.w3schools.com/jsref/event_onscroll.asp
https://developer.mozilla.org/en-US/docs/Web/API/Window/scrollY

Be careful when using this, sections wont have same size/px, when making site responsive