var w,h;

    if (document.all || document.layers) {
      w = screen.availWidth;
      h = screen.availHeight;
    }

  var popupW = 530, popupH = 420;

  var leftPos = (w-popupW)/2, topPos = (h-popupH)/2;

  function openWindow(winNum) {
  thePage = "/windows/window.cfm?page=" + winNum;
    window.open(thePage,'popupWindow','width=' + popupW + ',height=' + popupH + ',top=' + topPos + ',scrollbars=yes, left=' + leftPos);
  }