[jQuery] JQuery object from another frame?

[AlexK]

I have two frames: "code" and "display".  I can use JQuery API from
"display" where my "document" is, but do not know how to use it from
another ("code") frame.

What do I put in $()?

For example in tableSorter:

$(window.display.document + "#example").tablesorter() --- does not
work.

This is how it supposed to work:

<script>
  $(document).ready(function(){
    $("#example").tablesorter();
  });
  </script>

Thanks,

Alex.