Throttled, efficient scroll that only runs once per frame redraw (From MDN documentation https://developer.mozilla.org/en-US/docs/Web/Events/scroll)

optimizedScroll.js

;(function() {
    var throttle = function(type, name, obj) {
        var obj = obj || window;
        var running = false;
        var func = function() {
            if (running) { return; }
            running = true;
            requestAnimationFrame(function() {
                obj.dispatchEvent(new CustomEvent(name));
                running = false;
            });
        };
        // Original event is tied to a func that'll only trigger once every animation frame
        obj.addEventListener(type, func);
    };

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

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