1 files changed, 33 insertions, 0 deletions
diff --git a/static/js/footnoteBacklinks.js b/static/js/footnoteBacklinks.js
new file mode 100644
index 0000000..8c20098
--- /dev/null
+++ b/static/js/footnoteBacklinks.js
@@ -0,0 +1,33 @@
+// Assign unique IDs to the footnote references based on their hashes.
+function assignReferenceIds() {
+    const references = document.querySelectorAll('.footnote-reference');
+    for (const ref of references) {
+        ref.id = `ref:${ref.children[0].hash.substring(1)}`;
+    }
+}
+
+// Create backlinks for each footnote definition if a corresponding reference exists.
+function createFootnoteBacklinks() {
+    const footnotes = document.querySelectorAll('.footnote-definition');
+    for (const footnote of footnotes) {
+        const backlinkId = `ref:${footnote.id}`;
+
+        // Skip if there's no corresponding reference in the text (i.e. the footnote doesn't reference anything).
+        if (!document.getElementById(backlinkId)) continue;
+
+        const backlink = document.createElement('a');
+        backlink.href = `#${backlinkId}`;
+        backlink.className = 'footnote-backlink';
+        backlink.textContent = '↩';
+        footnote.lastElementChild.appendChild(backlink);
+    }
+}
+
+// Initialise the handlers for the footnote references and definitions.
+function initFootnotes() {
+    assignReferenceIds();
+    createFootnoteBacklinks();
+}
+
+// Wait for the window to load, then execute the main function.
+window.addEventListener('load', initFootnotes);