function scrollX() {
  if (document.body.scrollLeft)
    return document.body.scrollLeft;
  if (window.pageXOffset)
    return window.pageXOffset;
  return 0;
}

function scrollY() {
  if (document.body.scrollTop)
    return document.body.scrollTop;
  if (window.pageYOffset)
    return window.pageYOffset;
  return 0;
}

function truex(obj) {
  var tx = 0;
  do {
    tx += obj.offsetLeft;
    obj = obj.offsetParent;
  } while(obj);

  return tx - scrollX();
}

function truey(obj) {
  var ty = 0;
  do {
    ty += obj.offsetTop;
    obj = obj.offsetParent;
  } while(obj);

  return ty - scrollY();
}