Does the JavaScript typeof operator ever return an upper case string?
<p>I recently came across the following line of code:</p>

<pre><code>var type = (typeof x).toLowerCase();
</code></pre>

<p>Note that in the above code, <code>x</code> will only ever be a string, a number, or undefined. I questioned this, pointing out that the <a href="http://es5.github.com/#x11.4.3" rel="nofollow">specification (11.4.3)</a> states the values to be returned by the <code>typeof</code> operator, and all of them are already lower case.</p>

<p>It's worth noting that the specification leaves host objects free to return pretty much whatever they like, so in that case it <em>is</em> possible to get a string with some upper case letters (I don't whether that actually ever happens, but it is allowed). However, as already stated, in this case <code>x</code> is only ever a string, a number or undefined.</p>

<p>My question is, do any implementations of the <code>typeof</code> operator ever return anything other than a lower case string?</p>
