title: this.parentNode returns undefined when run using Firefox
body: <p>When the following code is run via Firefox and you click the X button, javascript returns tmpField as undefined. I need to get the parentNode of the button which is the div.</p>
  
  <pre><code>&lt;head&gt;
      &lt;title&gt;&lt;/title&gt;
      &lt;script type ="text/javascript"&gt;
          function RemoveItem() {
                  if (document.addEventListener) {
                      var container = document.getElementById("InputContainer");
                      var tmpField = this.parentNode;
                      alert("Field: " + tmpField);                 
                  }
          }
      &lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;table width="100%"&gt;
  &lt;tr&gt;
      &lt;td style="width: 10%; vertical-align:top;"&gt;Field:&lt;/td&gt;
      &lt;td id="InputContainer"&gt;
          &lt;div id="divInput1" style="display: inline;"&gt;
              &lt;input id="txtComment1" name="txtComment" type="text" maxlength="35" /&gt;
              &lt;input id="btnDelete1" value="X" type="button" name="btnDelete" onclick="RemoveItem()" /&gt;
          &lt;/div&gt;
      &lt;/td&gt;
  &lt;/tr&gt;
  &lt;/table&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>In my scenario, I dynamically create multiple divs within "InputContainer".  Each of those divs has the same structure containing a text box and the delete button (with IDs containing the next increment).  It is important for me to be able to return the parentNode of the button which will always be the div.  I have the code for it to work in IE but not Firefox.  Any ideas how to resolve?</p>
  
  <p>Thanks...</p>