How to change class on page scroll?

Question

Python

Hello everyone, for example, there is such a design.
The menu is fixed, how to make it so that when the site is scrolled, say by 300px, the scroll class is added to the
menu. Well, the class will be assigned a different text color in the menu.

And when scrolling back, the class was removed.

Answer 1

I can advise you to select a piece of code in NPP with tabs and press shift + tab

Answer 2

To convert existing tabs to spaces, press Edit->Blank Operations->TAB to Space.
If in the future you want to enter spaces instead of tab when you press tab key:
Go to Settings->Preferences...->Language (since version 7.1) or Settings->Preferences...->Tab Settings (previous versions )
Check Replace by space
https://stackoverflow.com/questions/455037/convert...

Answer 3

This question appears here more often than rabbits breed. Use search.
Ps: Here, I wrote, for example: How to make a block appear on scroll?