var popUpWin=0; function popUpWindow(URLStr, left, top, width, height) { if(popUpWin) { if(!popUpWin.closed) popUpWin.close(); } popUpWin = open(welcome.html, 'popUpWin', 'toolbar=no,location=no,directories=no,status=no,menub ar=no,scrollbar=no,resizable=no,copyhistory=yes,width='200',height='200',left='100', top='100',screenX='150',screenY='150''); }