title: How to replace the `no-js` class name by `js` on all elements?
body: <p>What I’m trying to do is to get the elements with the class name <code>no-js</code> and replace it with <code>js</code>.</p>
  <p>I have no idea how to do this.
  I tried Googling around but couldn’t find anything, so does anyone know how to do this?</p>
  <p>My goal is to have a menu show a drop-down navigation when clicked, but if JavaScript is disabled I want it to show on hover with CSS (I’ve already done that).</p>
  <p>I’ve put my code on <a href="https://jsfiddle.net/MrPumpkin22/v9dcC/10/" rel="nofollow noreferrer">JSFiddle</a>.</p>