function spinUpdate(id,delta,form)
{
   if (form == null) form = 'MainForm';
   window.top.status = '';
   var ctl  = eval("document."+form+"."+id);
   if (delta == "z") { ctl.value = "0"; return; }
   else if (delta == "o") { ctl.value = "1"; return; }
   else if (delta == "")  { ctl.value = ""; return; }
   var value = (ctl.value == "") ? delta : parseFloat(ctl.value) + delta;
   var value = Math.round(value*10000)/10000;
   if (value > 0)
   {
       ctl.value = value;
   }
}