title: Amp-html - Can I use amp-position-observer to call AMP.setState() used in amp-bind?
body: <p>Is possible to set the AMP state using amp-position-observer?</p>
  
  <p>I have tried the following code without success: </p>
  
  <pre><code>&lt;!doctype html&gt;
  &lt;html ⚡&gt;
  &lt;head&gt;
    &lt;script async="" src="https://cdn.ampproject.org/v0.js"&gt;&lt;/script&gt;
    &lt;script async custom-element="amp-bind" src="https://cdn.ampproject.org/v0/amp-bind-0.1.js"&gt;&lt;/script&gt;
    &lt;script custom-element="amp-position-observer" src="https://cdn.ampproject.org/v0/amp-position-observer-0.1.js" async&gt;&lt;/script&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
    &lt;p [text]="'Hello ' + foo"&gt;Hello World&lt;/p&gt;
    &lt;div class="spacer"&gt;&lt;/div&gt;
    &lt;amp-position-observer
      intersection-ratios="0"
      on="enter:AMP.setState({foo: 'amp-bind'})"
      layout="nodisplay"&gt;
    &lt;/amp-position-observer&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>