var popUpWin=0; 
var currentLocation=null; 
var returnLocation=null; 
function popUpWindow(URLStr, left, top, width, height) { 
	if (popUpWin) { 
		if(!popUpWin.closed) { popUpWin.close(); }
		else { currentLocation=null; returnLocation=null; } 
	} 
	popUpWin = open(URLStr, 'commments', 'toolbar=no,location=no,directories=no,status=yes,menubar=no,scrollbars=no,resizable=no,copyhistory=no,width='+width+',height='+height+',left='+left+', top='+top+',screenX='+left+',screenY='+top+''); 
}