function displayInfo(elem, info)
{
if (elem.id=="ContentBox")
{
if (info != "")
 {
  alert (info);
 }else{
  alert(elem + ' , top:' + elem.offsetTop + ' , height:' + elem.offsetHeight);
 }
}
}

function ApproxHeight(elem){
var h = 0;
//displayInfo(elem, "");
for (var i = 0; i < elem.childNodes.length;i++)
 {
  var el = elem.childNodes[i];
  if (el.offsetTop > h)
    h = el.offsetTop;

  if((el.offsetTop + el.offsetHeight) > h)
    h = el.offsetTop + el.offsetHeight;

  var apH = ApproxHeight(el);
  //displayInfo(elem, apH + ' ' + el.id + '   (' + el + ')');
  if((apH + el.offsetTop) > h)
    h = apH + el.offsetTop;
 }
return h;
}