If you've read our JavaScript tutorial in some detail you'll know
that you can dynamically write to an HTML page (even a frame page).
What Fred does is to test whether he's in a frame.
If he isn't, then he loads the frame, and passes his name to the
frame so the frame can write instructions to load him again! Jane does the same,
for the identical frame.
The best way to understand this is to view the source of the
pages, and then write your own test pages.