js 获取滚动距离

/**
 * THIRD FUNCTION
 * getPageScroll() by quirksmode.com
 *
 * @return Array Return an array with x,y page scroll values.
 */
function ___getPageScroll() {
  var xScroll, yScroll;
  if (self.pageYOffset) {
    yScroll = self.pageYOffset;
    xScroll = self.pageXOffset;
  } else if (document.documentElement && document.documentElement.scrollTop) {
    // Explorer 6 Strict
    yScroll = document.documentElement.scrollTop;
    xScroll = document.documentElement.scrollLeft;
  } else if (document.body) {
    // all other Explorers
    yScroll = document.body.scrollTop;
    xScroll = document.body.scrollLeft;
  }
  arrayPageScroll = new Array(xScroll, yScroll);
  return arrayPageScroll;
}