Edit in JSFiddle

for(let elem of document.querySelectorAll('*')) {
    elem.addEventListener("click", e => alert(`Capturing: ${elem.tagName}`), true);
    elem.addEventListener("click", e => alert(`Bubbling: ${elem.tagName}`));
  }
<body id='container'>
  <div>
    <a>Click me!</a>
  </div>
</body>