title: How to check if an object is an instance of a NodeList in IE?
body: <p>Why is NodeList undefined in IE6/7?</p>
  
  <pre><code>&lt;form action="/" method="post" id="testform"&gt;
      &lt;input type="checkbox" name="foobar[]" value="1" id="" /&gt;
      &lt;input type="checkbox" name="foobar[]" value="2" id="" /&gt;
      &lt;input type="checkbox" name="foobar[]" value="3" id="" /&gt;    
  &lt;/form&gt;
  
  &lt;script type="text/javascript" charset="utf-8"&gt;
  (function () {
      var el = document.getElementById('testform')['foobar[]']
      if (el instanceof NodeList) {
          alert("I'm a NodeList");
      }  
  })();
  &lt;/script&gt;
  </code></pre>
  
  <p>This works in FF3/Safari 3.1 but doesn't work in IE6/7. Anyone have any ideas how to check if el is an instance of NodeList across all browsers?</p>