JavaScript animated scrollTo

window.requestAnimFrame = (function(){
  return  window.requestAnimationFrame       ||
          window.webkitRequestAnimationFrame ||
          window.mozRequestAnimationFrame    ||
          function(callback){
            window.setTimeout(callback, 1000 / 60);
          };
})();

function animateScrollTo(id) {
  var node = document.getElementById(id);
  if (node) {
    var to = 0;
    var from = window.pageYOffset;
    do {
      to += node.offsetTop;
//      from += node.offsetParent ? node.offsetParent.scrollTop : 0;
      node = node.offsetParent;
    } while (node)
    if (from == to) return;
    var start = Date.now();
    var tick = function() {
      var t = Math.min(1, ((Date.now() - start) / 1000));
      var eased =  t<.5 ? 4*t*t*t : (t-1)*(2*t-2)*(2*t-2)+1;
      var val = (eased * (to - from)) + from;
      window.scrollTo(0, val);
      if (t<1) { 
        window.requestAnimFrame(tick);
      }
    };
    tick();
  }
}