Comment by chrismorgan

Related: one of my favourite code golfing tricks is named access on the Window object <https://html.spec.whatwg.org/multipage/window-object.html#na...>:

  <div id=result></div>
  <script>
      document.getElementById("result").textContent = "Why do it this way—";
      document.querySelector("result").textContent = "—or even this way—";
      result.textContent = "—when you can do it this way?";
  </script>

Edit: adding another similar test to this page, window[`test${i}`] is taking roughly twice as long as document.querySelector(`#test${i}`) in Firefox, but only half as long in Chromium—which is still a bit slower than document.getElementById(`test${i}`) in Chromium, and than window[`test${i}`] in Firefox.