title: Get original definition of redefined function
body: <p>I am writing a bookmarklet which performs some function on a page. As part of this function I need to use <code>getElementsByClassName</code>. However, during testing I found that several websites have redefined <code>getElementsByClassName</code> to a custom method. Presumably this was done in order to support <code>getElementsByClassName</code> in all browsers. </p>
  
  <p>The implementation of custom <code>getElementsByClassName</code> is a bit sloppy and fails for several of my use cases. Is there any way I could get the original definition of <code>getElementsByClassName</code>?</p>
  
  <p>In the chrome javascript console: <code>getElementsByClassName</code> points to a native function. Is there a way to access this native function, now that <code>getElementsByClassName</code> has been redefined?</p>