<style>
#container {
  text-align: center;
  width: 200px;
  height: 100px;
  background-color: red;
  position: relative;
}
#abs_pos {
  display: inline;
  position: absolute;
  left: 0px;
  top: 0px;
  background-color: green;
  width: 200px;
  height: 100px;
}
</style>
<div id=container>
  <div id=abs_pos></div>
</div>
<script>
document.body.offsetHeight;
let inline_content = document.createElement("span");
inline_content.innerText = "PASS if no red";
container.insertBefore(inline_content, abs_pos);
</script>
