Fantastic idea which should be an option on Wikipedia itself. After using the script for so long I've started to take for granted the fact that I can glance at footnotes instantly without scrolling or clicking down to the bottom of the page. When I use Wikipedia on browsers/devices which don't have this script installed it's amazing how much of a chore it is when researching something.
Thanks for writing this! Now all you gotta do is make it work on wiki-style pages all over the net :P
Script, where have you been all my wikipedia life?
Glad I didn't have to write it myself! :-)