var oWin=null;

function openPopup(iJaar,sUrl)
{
  if(!oWin || oWin.closed)
    oWin=window.open(iJaar+"/"+sUrl,"popup");
  else
    oWin.location=iJaar+"/"+sUrl;
  oWin.focus();
}

function closePopup()
{
  if(oWin && !oWin.closed)
    oWin.close();
}