title: Flickering of webpage when gtm.js loads
body: <p>I have a problem on our webpage when gtm.js loads asyncrounous. In the moment it happens our site "flickers", so you have feeling that the site is loaded 2 times. I have commented the script for GTM and there is no "flickering" anymore. I have tried placing the script call just after <code>&lt;body&gt;</code> tag and also at the bottom before closing <code>&lt;body&gt;</code> tag, but same thing happens. I've read somewhere that this is the downside of <code>async</code>? Is this true and how could I solve this? Has anyone had same experiences/problems?</p>
  
  <p>Snippet I use:</p>
  
  <pre><code>&lt;noscript&gt;&lt;iframe src="//www.googletagmanager.com/ns.html?id=GTM-XXXXXX"
  height="0" width="0" style="display:none;visibility:hidden"&gt;&lt;/iframe&gt;&lt;/noscript&gt;
  &lt;script&gt;(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
  new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
  j=d.createElement(s),dl=l!='dataLayer'?'&amp;l='+l:'';j.async=true;j.src=
  '//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
  })(window,document,'script','dataLayer','GTM-XXXXXX');&lt;/script&gt;
  </code></pre>
  
  <p>Thanks in advance.</p>