basic-shadow-2.html

Enable keyboard shortcuts

<!DOCTYPE HTML>

<html>

<head>

  <script>

    function tweak() {

      var shadowDiv = document.createElement("div");

      shadowDiv.style.border = "10px solid green";

      var shadowRoot = document.getElementById('outer').attachShadow({mode: 'open'});

      shadowRoot.appendChild(shadowDiv);

      var orangeDiv = document.createElement("div");

      orangeDiv.style.border = "10px solid orange";

      var purpleDiv = document.createElement("div");

      purpleDiv.style.border = "10px solid purple";

      shadowDiv.appendChild(purpleDiv);

      shadowDiv.insertBefore(orangeDiv, purpleDiv);

  </script>

</head>

<body onload="tweak()">

<div id="outer">

  <div style="background-color:red;"></div>

</div>

</body>

</html>