Image selection solution needed

[Stan Lieberman]

In a frames page there are two frames, left.htm and main.htm. In the same
directory are two images, img1.jpg and img2.jpg. In left.htm are two links
to main.htm, 1 and 2. When 1 is clicked, img1.jpg should appear in main.htm
and when 2 is clicked, img2.jpg should appear in main.htm. I would
appreciate someone showing me how this is done with JavaScript.

Thanks,
Stan