Untitled

<html>
<body>
<script>
window.onload = function() {
    var fn = function(a, b) { return a + b; };
    var n = 100000;
    var start = Date.now();
    for (var i = 0; i < n; i++) {
        String(fn);
    }
    document.write("<p><b>String(fn):</b> " + (Date.now() - start) / 1000 + " sec.</p>");

    var start = Date.now();
    for (var i = 0; i < n; i++) {
        fn + "";
    }
    document.write("<p><b>fn + \"\":</b> " + (Date.now() - start) / 1000 + " sec.</p>");
}
</script>
</body>
</html>