function popGrafiek(what)
{
   window["RfrntWndw"] = window.open(what, "RfrntWndw", 'dependent=1,toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=1,resizable=yes,width=810,height=500,left=10,top=10');
   window["RfrntWndw"].focus(); 
}