title: How to access shadow dow with jquery in a polymer.dart component
body: <p>In my polymer.dart component I want to access the shadow dom with jquery.
  In dart I can access f.e. an node´s id like this:</p>
  
  <pre><code>$["testname"].attributes["id"]
  </code></pre>
  
  <p>or </p>
  
  <pre><code>shadowRoot.querySelector("#testname").attributes["id"]
  </code></pre>
  
  <p>How is this done with jquery</p>
  
  <pre><code>context.callMethod(r'$', ['#testname'])["id"]
  </code></pre>
  
  <p>does not work obviously. </p>