Redefine undefined outside the scope

fiddle.html

<p>First, undefined is defined to <em id="step1"></em></p>
<p>Then, undefined is redefined to <em id="step2"></em></p>

fiddle.js

$(document).ready(function() {
  undefined = false;
  $("#step1").text();
  /* We create a self-invoking function to refefine undefined to undefined */
  (function() { window.undefined = undefined })();
  $("#step2").text(undefined);
});

fiddle.manifest

normalize_css: no