css/css-position/position-absolute-dynamic-static-position-margin-001.html

<!DOCTYPE html>
<html class='reftest-wait'>
<link rel="match" href="../reference/ref-filled-green-100px-square-only.html">
<link rel="help" href="https://www.w3.org/TR/css-position-3/" />
<meta name="assert" content="This test checks that a dynamic change in constraints calculates the static position correctly."/>
<script src="/common/reftest-wait.js"></script>
<style>
#container {
  position: relative;
  background: red;

  box-sizing: border-box;
  border: solid green 10px;
  width: 100px;
  height: 100px;
}

#block {
  background: green;
  height: 40px;
  margin-bottom: 20px;
}

#target {
  position: absolute;
  background: green;

  width: 80px;
  height: 20px;
  top: -10px;
  left: -10px;
}

#cover {
  position: absolute;
  background: green;

  width: 80px;
  height: 20px;
  top: 40px;
  left: 0px;
}
</style>
<p>Test passes if there is a filled green square.</p>
<div id="container">
  <div id="block"></div>
  <div id="target"></div>
  <div id="cover"></div>
</div>
<script>
document.body.offsetTop;
const target = document.getElementById('target');
target.style.top = 'initial';
target.style.left = 'initial';
document.body.offsetTop;
takeScreenshot();
</script>