What object is .getElementById() originally attached to?
<p>I'd like to modify the prototype of whatever object is responsible for <code>.getElementById()</code></p>

<p>I know <code>document</code> does not have a prototype, so what object is <code>.getElementById()</code> actually attached to?</p>

<p>Edit: so turns out document does have a prototype (thanks Kevin). I feel silly.</p>
