[jQuery] $ is not defined error

[jQuery] $ is not defined error


I'm modifying the Drupal img_assist module, and trying to add a little
jquery to the popup it creates. When I do, I get this error:
$ is not defined
When I view source, I see the jquery init code at the bottom of the
html for both the page frameset, and for both of the framed pages (the
popup uses frames).