How to block scrolling on mobile?

Question

Layout

Good day, the question is. There is a dropdown menu, quite large. The problem is that when you open it, it goes down, the sticky-top panel, so when you try to scroll the menu, the body scrolls first, and then the menu. Here's how to fix it so that when the menu is opened, the body does not scroll, but the menu scrolls right away. Accordingly, when the menu was closed, this parameter was removed. Something no ideas (

Answer 1

Give the menu itself a scroll and limit its maximum height

Answer 2

When opening a dropdown, add a class to body or html
.mobile-scroll-hide {
overflow: hidden;
}