JS-TOC - Javascript Generated Table of Contents

js-toc.css

/* JS-TOC */
.js-toc-w:hover {
  opacity: 1;
  width: 220px;
}

.js-toc-w {
  position: fixed;
  top: 280px;
  padding: 10px 15px 10px 10px;
  opacity: .6;
  font-size: 90%;
  line-height: 1.3;
  background: #fff;
  width: 25px;
  box-shadow: rgba(0,0,0,0.2) 0 0 5px;
  border-top-right-radius: 6px;
  border-bottom-right-radius: 6px;
  transition: all .2s linear;
  border-right: 2px solid #4caf50;
  overflow: hidden;
}

.js-toc {
  width: 200px;
  list-style: none;
  padding-left: 15px;
}

.js-toc li.js-toc-h {
  text-transform: uppercase;
  color: #aaa;
  font-size: 12px;
  transform: rotate(-90deg);
  position: absolute;
  left: -20px;
  top: 50%;
  border: 0;
}

.js-toc li {
  padding: 3px;
  border-bottom: 1px solid #ddd;
}

.js-toc li:last-child {
  border: 0;
}

@media(max-width:1640px) {
  .js-toc-w {
    display: none;
  }
}

js-toc.js

<script>if(tc=".h-e",hs=".e-content h3",d=document,h=d.querySelectorAll(hs),h.length>0){for(toc=d.createElement("ul"),toc.className="js-toc list-style-none bx pad shadow",i=0;i<h.length;i++)l=d.createElement("a"),h[i].id=h[i].innerText.toLowerCase().replace(/[^a-z0-9áéíóúñü \.,_-]/gim,"").replace(/\s+/gim,"-").trim(),l.text=h[i].innerText,l.href=location.href.replace(location.hash,"")+"#"+h[i].id,hl=d.createElement("li"),hl.appendChild(l),toc.appendChild(hl);t=d.querySelector(tc),t.appendChild(toc)}</script>