function show_tip(tnode, symbol)
 {
   var tooltip = document.getElementById('tooltip_'+symbol);
   if (tooltip == null)
     return;
   var X=tnode.offsetLeft;
   tempEl=tnode.offsetParent;
   while (tempEl != null) 
   {
     X+=tempEl.offsetLeft;
     tempEl=tempEl.offsetParent;
   }
   var Y=tnode.offsetTop;
   tempEl=tnode.offsetParent;
   while (tempEl != null) 
   {
     Y+=tempEl.offsetTop;
     tempEl=tempEl.offsetParent;
   }
   var extrax = 4;
   if (typeof(document.all)=='undefined') extrax = 0;
   tooltip.style.left = (X+tnode.offsetWidth-tooltip.offsetWidth+extrax)+'px';
   tooltip.style.top = (Y+tnode.offsetHeight)+'px';
   tooltip.style.visibility = 'visible';
 }
 function hide_tip(symbol)
 {
   var tooltip = document.getElementById('tooltip_'+symbol);
   if (tooltip == null)
     return;
   tooltip.style.visibility = 'hidden';
 }