HTML and JavaScript implementation of the Clear-Text Footnotes Specification

Render source annotations like ƒ(note) into superscript footnotes, or reverse rendered footnotes back into source annotations. Mixed rendered/source input is normalized during rendering.

The code for this is at GitHub footnotes-js-html and the explanation of what this is Clear-Text Footnotes Specification

Implemented behavior

• Source annotations use ƒ(...); note text is single-line and trimmed.
• Horizontal whitespace immediately before a source marker is collapsed during rendering.
• Balanced parentheses are supported inside source notes.
• References use Unicode superscript digits: ¹, ², ¹⁰.
• A final rendered block is introduced by --- and entries like 1) note.
• Malformed source annotations or rendered blocks fail without partial output.