When scrolling the site, how to add a new item to the top pinned menu?

Question

css

Good afternoon! I have a menu on the site that is fixed at the top when scrolling the site. Now there is a task when scrolling to add a new menu item, but so that it appears only at the moment when the site is scrolled. How can this be implemented?

Answer 1

Using js to track the scroll and create a new element and add it to the menu. Or you can create it right away, but hide it. When the desired scroll value is reached, show it.