<!DOCTYPE html>
<html>
<head>
	<style type="text/css">
		#page-header {
			position: running(header);
		}
		.showRunningAttempt::after {
			content: element(header);
		}
	</style>
</head>

<body>
	<div>
		<p id="page-header">Running element content.</p>
	</div>
	<div id="page-content" class="showRunningAttempt">
		<p>Page 1.</p>
	</div>
</body>
</html>