Normalize mousewheel event across browsers

normalize_mousewheel.js

// http://stackoverflow.com/questions/5527601/normalizing-mousewheel-speed-across-browsers

function normalize_mousewheel(e) {
    var //o = e.originalEvent,
        o = e,
        d = o.detail, w = o.wheelDelta,
        n = 225, n1 = n-1;
    
    // Normalize delta
    d = d ? w && (f = w/d) ? d/f : -d/1.35 : w/120;
    // Quadratic scale if |d| > 1
    d = d < 1 ? d < -1 ? (-Math.pow(d, 2) - n1) / n : d : (Math.pow(d, 2) + n1) / n;
    // Delta *should* not be greater than 2...
    e.delta = Math.min(Math.max(d / 2, -1), 1);
}



/* Quick cross browser event attach - this is bad mmkay */
var node = document.getElementById('scrollme');

function listener(e) {
    normalize_mousewheel(e);
    node.scrollTop -= 40 * e.delta;
}

if ('onmousewheel' in node) {
    node.onmousewheel = function(e) {
        e = e || window.event;
        listener(e);
    }
} else {
    node.addEventListener('DOMMouseScroll', listener)
}