PerformanceTests/Parser/query-selector-deep.html

<!DOCTYPE html>
<html>
<body>
<script src="../resources/runner.js"></script>
<script>
var parentDiv = document.body;
for (var i = 0; i < 1000; i++) {
    var div = document.createElement("div");
    div.id = "foo" + i;
    div.className = "bar" + i;
    parentDiv.appendChild(div);
    parentDiv = div;
}

var h1 = document.createElement("h1");
h1.id = "id";
h1.className = "class";
parentDiv.appendChild(h1);

PerfTestRunner.measureRunsPerSecond({
    description: "This benchmark tests querySelector() for an element that appears in the depths in the document",
    run: function() {
        for (var i = 0; i < 100; i++) {
            document.querySelector("h1");
            document.querySelector("#id");
            document.querySelector(".class");
        }
    }});
</script>
</body>
</html>