<html>
<script>
  (function() {
    var crossOrigin = 'http://localhost:8000';
    var filePath = "/page_load_metrics/empty.js";
    var src = crossOrigin + filePath;
    document.write('<scr' + 'ipt src="' + src + '" async></scr' + 'ipt>');
  })();
</script>
<body>
  This page uses document.write to load external js.
</body>