LayoutTests/intersection-observer/resources/no-document-leak-frame.html - WebKit - Git at Google

 <!DOCTYPE html>
 <div id="target"></div>

 <script>
 var target = document.getElementById("target");
 var observer = new IntersectionObserver(function() { });
 observer.observe(target);
 </script>
	<!DOCTYPE html>
	<div id="target"></div>

	<script>
	var target = document.getElementById("target");
	var observer = new IntersectionObserver(function() { });
	observer.observe(target);
	</script>