chromium/third_party/blink/perf_tests/parser/query-selector-all-first.html

<!DOCTYPE html>
<html>
<body>
<h1 id="id" class="class"></h1>
<script src="../resources/runner.js"></script>
<script>
PerfTestRunner.measureRunsPerSecond({
    description: "This benchmark tests querySelectorAll() for an element that appears near the head of the document",
    run: function() {
        for (var i = 0; i < 1000; i++) {
            document.querySelectorAll("h1");
            document.querySelectorAll("#id");
            document.querySelectorAll(".class");
        }
    }});
</script>
</body>
</html>