How to finalize the landing page menu?

Question

css

I make up a website, landing page. I am using twitter bootstrap. When scrolling down, I would like the list class to change to "active".
If I understand correctly, then you need to hang an html anchor on each part of the page. I made a menu when the class is clicked, and the cap immediately disappears. It only appears when you swipe your mouse over it.
Question:
How to make the list class change to "active"
1) When you click on the + link, it immediately jumps to that part of the page.
2) When scrolling to part of the page.
Thanks in advance for your reply.

Answer 1

lnked.ru/js/vybor_punkta_menyu_pri_skrollinge
try my implementation, it can also be done with the history api if necessary, I will give an example in the same plugin implemented

Answer 2

Do you have the letter "y" on your keyboard?

Answer 3

Thanks to all.

Answer 4

getapitchdeck.com/demo/? Here is an example of such a page in another topic, see how it is implemented.