Detangle src/readtheorg_theme/js/readtheorg.js

src/readtheorg_theme/readtheorg.org

@@ -1432,6 +1432,26 @@ for nice yellow or orange boxes.
 :END:
 
 #+begin_src js
+function collapse_toc_elements_on_click (nav_li_a){
+    /*
+      When an `a' element in the TOC is clicked, its parent
+      `li' element's active attribute is toggled.  This causes
+      the element to toggle between minimized and maximized
+      states.  The active attribute is documented in bootstrap.
+      https://getbootstrap.com/docs/4.0/components/navbar/#nav
+    */
+    $(nav_li_a).parent().toggleClass("active");
+}
+
+$( document ).ready(function() {
+    // When the document is loaded and ready, bind the
+    // function `collapse_toc_elements_on_click' to the
+    // `a' elements in the table of contents.
+    $("#text-table-of-contents a").click(function() {
+        collapse_toc_elements_on_click(this);
+    });
+});
+
 $(function() {
     $('.note').before("<p class='admonition-title note'>Note</p>");
     $('.seealso').before("<p class='admonition-title seealso'>See also</p>");