<!DOCTYPE HTML>
<head>
<meta charset="UTF-8">
<title>CSS Test Reference: dynamic changes to offset properties</title>
<link rel="author" title="L. David Baron" href="https://dbaron.org/">
<link rel="author" title="Mozilla" href="https://www.mozilla.org/">
<style>

body {
  margin: 0;
}

#container {
  position: absolute;
  width: 100px;
  height: 100px;
  background: yellow;
}

#abspos {
  margin-top: 10px;
  margin-left: 70px;
  width: 10px;
  height: 10px;
  background: fuchsia;
}

</style>

<div id="container">
  <div id="abspos"></div>
</div>