spec/head.html

  <link rel="stylesheet" type="text/css" href="normalize.css">
  <link rel="stylesheet" type="text/css" href="tocbot.css">
  <link rel="stylesheet" type="text/css" href="style.css">
  <script src="tocbot.min.js"></script>
  <script>
    function ready(fn) {
      if (document.attachEvent ? document.readyState === "complete" : document.readyState !== "loading"){
        fn();
      } else {
        document.addEventListener('DOMContentLoaded', fn);
      }
    }

    ready(function() {
      tocbot.init({
        // Where to render the table of contents.
        tocSelector: '#toc',
        // Where to grab the headings to build the table of contents.
        contentSelector: '#content',
        // Which headings to grab inside of the contentSelector element.
        headingSelector: 'h2, h3, h4, h5, h6',
        collapseDepth: 3,
        positionFixedSelector: "#toc",
      });
    })
  </script>