var popUpWin=0;
function popUpWindow(URLStr, pwidth, pheight){
	
  if(popUpWin){
    if(!popUpWin.closed) popUpWin.close();
  }
  
  var screenWidth = screen.width;
  var screenHeight = screen.height;
  
  left = (screenWidth - pwidth)/2
  vtop = (screenHeight - pheight)/2  
  
 // alert(left+" : "+top)
  
  popUpWin = open(URLStr, 'popUpWin', 'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=no,copyhistory=yes,width='+pwidth+',height='+pheight+',left='+left+', top='+vtop+',screenX='+left+',screenY='+vtop+'');
}