function GetOffsetPos(obj)
{
  var pos = { top: 0
            , left: 0
            };
  while (obj)
  {
    pos.top += obj.offsetTop;
    pos.left += obj.offsetLeft;
    obj = obj.offsetParent;
  }
  return pos;
}

function DisplayDescr(curobj,obj)
{
  var descr = document.getElementById(obj);
  var curobj_pos = GetOffsetPos(curobj);
  descr.style.top = (curobj_pos.top-30)+"px";
  descr.style.left = (curobj_pos.left+180)+"px";
  descr.style.display = "block";
  
}

function HideDescr(obj)
{
  document.getElementById(obj).style.display = "none";
}