title: Polymer: get the value of paper-input inside a paper-dialog after paper-button press "ok"
body: <p>i need to get the value of some paper-input fields inside a paper-dialog after a press on a "ok" paper-button.</p>
  
  <p>I have:</p>
  
  <pre><code>...
  &lt;paper-dialog id="notediag" heading="Add Note" transition="paper-dialog-transition-center"&gt;
      &lt;paper-input id="dialog-add-note-header" label="Header"
          value="{{valHeader}}"&gt;&lt;/paper-input&gt;
      &lt;br&gt;
      &lt;paper-input id="dialog-add-note-text" label="Text"&gt;&lt;/paper-input&gt;
  
      &lt;paper-button label="Cancel" dismissive&gt;&lt;/paper-button&gt;
      &lt;paper-button label="Ok" affirmative default
          on-click="{{addNote}}"&gt;&lt;/paper-button&gt;
  &lt;/paper-dialog&gt;
  ...
  
  &lt;script&gt;
  Polymer('note-list',{
    addNote: function(e, detail, sender)
    {
          var header=???
          console.log("add note "+header);
    }
  });
  &lt;/script&gt;
  </code></pre>
  
  <p>I tried multiple ways to find the values of the paper-input fields but not found a propper way to do it. <code>e.target.templateInstance</code> does not work. A call to <code>document.querySelector('#dialog-add-note-header')</code> results in a null.</p>
  
  <p>Any ideas?</p>
  
  <p>Thanks for you help.</p>
  
  <p>Stefan</p>