function xwin(url, name, width, height, features){
  var l = (window.screen.availWidth) ? (window.screen.availWidth - width)/2 : 0;
  var t = (window.screen.availHeight) ? (window.screen.availHeight - height)/2 : 0;
  if (typeof(features) == 'string')
     features = ',' + features;

  var w = window.open(url, name, 'top=' + t + ',left=' + l + ',height=' + height + ',width=' + width + features);
  w.resizeTo(width, height);
  return w;
}