css/css-overflow/column-scroll-marker-002.html

<!DOCTYPE html>
<html class="reftest-wait">
  <link rel="author" title="Morten Stenshorne" href="mailto:mstensho@chromium.org">
  <link rel="help" href="https://www.w3.org/TR/css-multicol-2/#column-pseudo">
  <link rel="match" href="column-scroll-marker-002-ref.html">
  <script src="/resources/testdriver.js"></script>
  <script src="/resources/testdriver-actions.js"></script>
  <script src="/resources/testdriver-vendor.js"></script>
  <style>
    #container {
      overflow: hidden;
      columns: 3;
      column-fill: auto;
      gap: 0;
      orphans: 1;
      widows: 1;
      height: 100px;
      border: 15px solid;
      line-height: 20px;
      scroll-marker-group: before;
      background: yellow;
    }
    #container::scroll-marker-group {
      display: flex;
      justify-content: space-between;
      height: 50px;
      background: cyan;
    }
    #container::column::scroll-marker {
      display: flex;
      justify-content: center;
      align-items: center;
      width: 50px;
      height: 50px;
      background: hotpink;
      content: "*";
    }
  </style>
  <div style="width:450px;">
    <div id="container">
      First column<br>
      <br>
      <br>
      <br>
      <br>
      Second column<br>
      <br>
      <br>
      <br>
      <br>
      Third column<br>
      <br>
      <br>
      <br>
      <br>
      Fourth column<br>
      <br>
      <br>
      <br>
      <br>
      Fifth column<br>
    </div>
  </div>
  <script>
    async function run() {
      actions_promise = new test_driver.Actions()
        .pointerMove(310, 10)
        .pointerDown()
        .pointerUp()
        .send();
      await actions_promise;
      document.documentElement.classList.remove("reftest-wait");
    }
    run();
  </script>
</html>