Footnotes on the web are a pain in the ass. You click on a tiny number, get transported somewhere near the bottom of the page, find the footnote you were looking for, and click on a link to go back to where you were on the page
This script looks to make that whole process painless. It automatically detects the footnote link and content turns the link into an easy-to-click button, and puts up a popover when the reader clicks on the footnote button.
The script and default styles are built to work great on any size viewport; the popover will be positioned on the top/ bottom automatically (based on the relative amount of space), will update its location as the viewport changes size, and will ensure that the popover never scrolls offscreen. All of that adds up to a much-improved user experience.