var popUpWin=0;

function popupwindow(URLStr, width, height)
{
  if(popUpWin)
  {
    if(!popUpWin.closed) popUpWin.close();
  }
var popWidth  = width + 20;
var popHeight = height + 20;  
popUpWin = open(URLStr, 'popUpWin', 'titlebar=yes,toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbar=yes,resizable=yes,copyhistory=yes,width='+popWidth+',height='+popHeight+',left=50,top=50,screenX=100,screenY=100');
}