You can choose to have Footnotes exported.
Create your footnotes in the usual way.
In this sample we have used the HINT tooltip library. When the text frame is exported as text the footnotes are appended to the end of the HTML text with hyperlinks to the note locator.
* HINT.css is a tooltip library made in pure CSS.
* Source: https://github.com/chinchang/hint.css
* Demo: http://kushagragour.in/lab/hint/
* Release under The MIT License