function popUpWindow(url, w, h, nm, x, y, atts) {
  nm = nm || "subwindow";
  atts = atts || "location=no,menubar=no,resizable=no,scrollbars=no,status=yes";
  w = w || 500; h = h || 760;

  x = (typeof x=="number")? x: window.opera? 100: Math.round( (screen.availWidth - w)/2 );
  y = (typeof y=="number")? y: window.opera? 20: Math.round( (screen.availHeight - h)/2 );

  atts += ',width='+w+',height='+h+',left='+x+',top='+y;
  var win = window.open(url, nm, atts); 
  if (win) {
    if (!win.closed) { win.resizeTo(w,h); win.moveTo(x,y); win.focus(); return false; }
  } 
  return true;
}