css-scoping-shadow-nested-slot-display-override.html

<!DOCTYPE html>
<title>CSS Scoping: Dynamically overriding nested slot display value</title>
<link rel="author" title="Rune Lillesveen" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-scoping/#slots-in-shadow-tree">
<link rel="match" href="reference/green-box.html"/>
<style>
  #outerHost {
      width: 100px;
      height: 100px;
      background: red;
  }
</style>
<p>Test passes if you see a single 100px by 100px green box below.</p>
<div id="outerHost"> </div>
<script>
  let outerRoot = outerHost.attachShadow({mode:"open"});
  outerRoot.innerHTML = '<div id="innerHost"><slot></slot></div>';
  let innerHost = outerRoot.querySelector("#innerHost");
  let innerRoot = innerHost.attachShadow({mode:"open"});
  innerRoot.innerHTML = '<slot style="display:none; border:solid 50px green"></slot>';
  document.body.offsetTop;
  innerRoot.querySelector("slot").style.display = "block";
</script>

chromium/third_party/blink/web_tests/external/wpt/css/css-scoping/css-scoping-shadow-nested-slot-display-override.html