One of the whorst JS-Scroll 'Handler' ever. Don't use this shit! 😤

wtf-smooth-scroll.js

/*** Smooth scroll (IE-Scroll-Fix) ***/
Math.easeOut = function(t, b, c, d) {
    t /= d;
    return -c * t * (t - 2) + b;
};
(function() {
    // do not mess global space
    var
        interval,
        // scroll is being eased
        mult = 0,
        // how fast do we scroll
        dir = 0,
        // 1 = scroll down, -1 = scroll up
        steps = 30,
        // how many steps in animation
        length = 50; // how long to animate
    function MouseWheelHandler(e) {
        e.preventDefault(); // prevent default browser scroll
        clearInterval(interval); // cancel previous animation
        ++mult; // we are going to scroll faster
        var delta = -Math.max(-1, Math.min(1, (e.wheelDelta || -e.detail)));
        if (dir != delta) {
            // scroll direction changed
            mult = 1; // start slowly
            dir = delta;
        }
        for (var tgt = e.target; tgt != document.documentElement; tgt = tgt.parentNode) {
            var oldScroll = tgt.scrollTop;
            tgt.scrollTop += delta;
            if (oldScroll != tgt.scrollTop)
                break;
        }
        var start = tgt.scrollTop;
        var end = start + length * mult * delta; // where to end the scroll
        var change = end - start; // base change in one step
        var step = 0; // current step
        interval = setInterval(function() {
            var pos = Math.easeOut(step++, start, change, steps);
            //window.scrollTo(0,pos);
            tgt.scrollTop = pos;
            if (step >= steps) {
                // scroll finished without speed up - stop by easing out
                mult = 0;
                clearInterval(interval);
            }
        }, 10);
    }
    if (window.addEventListener) {
        window.addEventListener("mousewheel", MouseWheelHandler, false);
        window.addEventListener("DOMMouseScroll", MouseWheelHandler, false);
    }
})();