css/cssom/all-initial-csstext.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>CSSOM: cssText round-trip with `all: initial`</title>
  <link rel="author" title="Peng Zhou" href="mailto:zhoupeng.1996@bytedance.com">
  <link rel="help" href="https://drafts.csswg.org/cssom/#dom-cssstyledeclaration-csstext">
  <link rel="help" href="https://drafts.csswg.org/cssom/#css-declaration-blocks">
  <link rel="match" href="all-initial-csstext-ref.html">
  <style>
    .test {
      all: initial;
      display: block;
      border: 1px solid #ccc;
      padding: 10px;
    }
  </style>
</head>
<body>
  <div class="test">First Element</div>
  <br/>
  <div class="test-clone">Clone element</div>
  <script>
    const styleSheet = document.styleSheets[0];
    const cssText = styleSheet.cssRules[0].style.cssText;
    styleSheet.insertRule('.test-clone { ' + cssText + ' }', 1);
  </script>
</body>
</html>