title: Facebook Pixel + Google Tag Manager + fbq events
body: <p>I'm using Google Tag Manager to deliver Facebook Pixel. </p>
  
  <p>Then, I fire events using code like this  </p>
  
  <pre><code>  &lt;body&gt;
  ...
          &lt;script&gt;
              fbq('track', 'ViewContent', { 
                  content_type: 'product',
                  content_ids: ['1234'],
                  content_name: 'ABC Leather Sandal',
                  content_category: 'Shoes',
                  value: 0.50,
                  currency: 'USD'
              });
          &lt;/script&gt;
      &lt;/body&gt;
  </code></pre>
  
  <p>But when the code is executed I got an error since Facebook Pixel is loaded asynchronously and fbq is not available yet.</p>
  
  <blockquote>
    <p>Uncaught ReferenceError: fbq is not defined</p>
  </blockquote>
  
  <p>What should I do?</p>