cross-shadow-boundary-select-root.html

<!doctype html>
<head>
<link rel=match href="cross-shadow-boundary-select-root-ref.html">
</head>
<div id="outerText1">OuterText1</div>
<div id="host1"></div>
<div id="outerText2">OuterText2</div>
<div id="host2"></div>
<div id="host3"></div>
<script>
  const outerText1 = document.getElementById("outerText1");
  const outerText2 = document.getElementById("outerText2");

  const host1 = document.getElementById("host1");
  const root1 = host1.attachShadow({mode: "open"});
  root1.innerHTML = "InnerText1";

  const host2 = document.getElementById("host2");
  const root2 = host2.attachShadow({mode: "open"});
  root2.innerHTML = "InnerText2";

  getSelection().setBaseAndExtent(outerText1, 0, root2, root2.childNodes.length);
</script>

chromium/third_party/blink/web_tests/external/wpt/selection/shadow-dom/cross-shadow-boundary-select-root.html