Predefined Javascript Objects

<script type='text/javascript'>

  function write_properties(o) {
   if (typeof(o) == 'object') {
     document.writeln("<ul>" );
     for (x in o) {
       document.writeln("<li>" + x + " (" + typeof(o[x]) + ")");
     }
     document.writeln("</ul>");
   }
  }

  write_properties(window);

</script>