"Type of undefined" vs "=== undefined" · jsPerf

JavaScript performance comparison Revision 6 of this test case created by Mihai Bazon on 2012-9-16 Preparation code <script> Benchmark.prototype.setup = function() { var a = 1, b = true, c = "c", d = [], e = {}, u; }; </script> Test runner Warning! For accurate results, please disable Firebug before running the tests. (Why?) Java applet disabled.

[muvoiaia]

ブラウザテスト

[teramako]

僕はvoid 0派。というか == null 派かな(undefinedとnullの区別は付けない)。