title: toUpperCase() is not making the string upper case
body: <p>I don't know what I'm doing wrong;
  But somehow <code>.toUpperCase()</code> String-function is not working on my browser
  or do I get something wrong?</p>
  <pre><code>var string =&quot;kjsdgfiIJHBVSFIU&quot;;
  string.toUpperCase();
  console.log(string);
  </code></pre>
  <p><a href="http://jsbin.com/axorer/3/edit" rel="nofollow noreferrer">Live demo</a></p>