The JavaScript scroll event isn't very peformant this MDN snippet fixes that with a modified event.

optimizedScroll.js

(function() {
	'use strict';
	var throttle = function(type, name, obj) {
		obj = obj || window;
		var running = false;
		var func = function() {
			if (running) { return; }
			running = true;
			obj.requestAnimationFrame(function() {
				obj.dispatchEvent(new CustomEvent(name));
				running = false;
			});
		};
		obj.addEventListener(type, func);
	};

	/* init - you can init any event */
	throttle ('scroll', 'optimizedScroll');
})();

// handle event
window.addEventListener('optimizedScroll', function() {
	'use strict';
  console.log('Resource conscious scroll callback!');
});