How to calculate the scroll step?

Question

JavaScript

What are the solutions to calculate the scroll step (difference between the previous and next value). It doesn't matter how the page scrolls with the mouse wheel or in any other way.

Answer 1

var $win = $(window), $doc = $(document), prevPoint = $win.scrollTop();

$doc.scroll(function(){
   var curScroll = $win.scrollTop();
   console.log( curScroll - prevPoint );
   prevPoint = curScroll; 
});

But here's the catch - onscroll works randomly, the resulting gaps can hardly be called steps.