How to change css property simultaneously with page scroll?

Question

JavaScript

For example, there is St.

position: fixed;
top: 50px;

It is necessary that top changes relative to page scrolling until it reaches 0, and then it is fixed. With fixation, for example, you can do this:

if (document.body.scrollTop > 50 || document.documentElement.scrollTop > 50)

But how to do the rest?

Answer 1

https://learn.javascript.ru/onscroll