How to implement fixed blocks in the sidebar?

Question

JavaScript

What is the most efficient way to implement fixed blocks in the sidebar that change based on scrolling?
Mail.ru example: https://health.mail.ru/news/ukradennyy_chas_vredno...
When scrolling to the right, a block appears, then changes several times.
Interested in any solutions: ready-made plugins, their own solutions. Thank you.

Answer 1

You can do everything with a simple js scroll .... Example: jsfiddle.net/szdw12u3