css/css-grid/abspos/grid-item-absolute-positioning-dynamic-001.html

<!DOCTYPE html>
<html lang=en class="reftest-wait">
<meta charset="utf-8">
<title>CSS Grid Layout Test: Grid item absolute positioning dynamic</title>
<link rel="author" title="Manuel Rego Casasnovas" href="mailto:rego@igalia.com">
<link rel="help" href="https://drafts.csswg.org/css-grid-1/#abspos" title="9. Absolute Positioning">
<link rel="match" href="../../reference/ref-filled-green-200px-square.html">
<meta name="assert" content="This test checks that a grid item which becomes an absolutelly positioned children of a grid.">
<style>
#wrapper {
  width: 200px;
  height: 200px;
  position: relative;
  background: red;
}

#grid {
  display: grid;
  grid: 100px / 100px;
}

#item {
  background: green;
  width: 100%;
  height: 100%;
}
</style>

<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>

<div id="wrapper">
  <div id="grid">
    <div id="item"></div>
  </div>
</div>

<script>
  window.requestAnimationFrame(() => {
    document.getElementById("item").style.position = "absolute";
    document.body.offsetLeft;
    document.documentElement.classList.remove('reftest-wait');
  });
</script>

</html>