</head>
<body>
  <p>Test passes if you see a green square.</p>
  <div style="background: green; color: red; width: 200px; height: 200px;">
    <math><mfrac style="visibility: hidden"><mn>1</mn><mn>2</mn></mfrac></math>
    <div id="dynamic">
      <math><mfrac><mn>1</mn><mn>2</mn></mfrac></math>
    </div>
  </div>
  <script src="/mathml/support/feature-detection.js"></script>
  <script>
    window.addEventListener("load", () => {
        document.getElementById("dynamic").style.visibility = "hidden";
     