function currentYPosition() {
   if (self.pageYOffset)
       return self.pageYOffset;
   if (document.documentElement && document.documentElement.scrollTop)
      return document.documentElement.scrollTop;
   if (document.body.scrollTop)
       return document.body.scrollTop;
   return 0;
}
function elmYPosition(eID) {
   var elm  = document.getElementById(eID);
   var y    = elm.offsetTop;
   var node = elm;
   while (node.offsetParent && node.offsetParent != document.body) {
      node = node.offsetParent;
      y   += node.offsetTop;
   } return y;
}
function smoothScroll(eID) {
   var startY   = currentYPosition();
   var stopY    = elmYPosition(eID);
   var distance = stopY > startY ? stopY - startY : startY - stopY;
   if (distance < 100) {
      scrollTo(0, stopY); return;
   }
   var speed = Math.round(distance / 100);
   var step  = Math.round(distance / 25);
   var leapY = stopY > startY ? startY + step : startY - step;
   var timer = 0;
   if (stopY > startY) {
      for ( var i=startY; i<stopY; i+=step ) {
         setTimeout("window.scrollTo(0, "+leapY+")", timer * speed);
         leapY += step; if (leapY > stopY) leapY = stopY; timer++;
      } return;
   }
   for ( var i=startY; i>stopY; i-=step ) {
      setTimeout("window.scrollTo(0, "+leapY+")", timer * speed);
      leapY -= step; if (leapY < stopY) leapY = stopY; timer++;
   }
}