eight: 100px;
}
#spacer {
  height: 3000px;
}
.hidden {
  content-visibility: hidden;
}
</style>

<div id="target1">
  <div id="target2"></div>
</div>
<div id="target3">
  <div id="target4"></div>
</div>
<div id="spacer"></div>
<div id="find_me"></div>

<script>
async_test((t) => {
  let target1, target2, target3, target4;
  let observer;
  let entries = [];

  // Set everything up.
  function enqueueStep1() {
    target1 = document.getElementById("target1");
    target2 = document.getElementById("target2")