title: Difference between loading javascript file via async=false and script tag without async attribute
body: <p><strong>First Way:</strong></p>
  
  <pre><code>&lt;script type="text/javascript" src="jquery.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p><strong>Second Way:</strong></p>
  
  <pre><code>var js = document.createElement("script");
  js.type = "text/javascript";
  js.src = "jquery.js";
  js.async = false;//THIS ATTRIBUTE
  
  var h = document.getElementsByTagName("head")[0];
  h.parentNode.appendChild(js);
  </code></pre>
  
  <p>Question: What is the difference between above two ways. <strong>Google Page Speed Insight</strong> Tool doesn't complain about <code>First Way</code> as <code>Render blocking issue</code>.</p>
  
  <p>FYI: We have to load <code>jQuery</code> file without <code>async</code> because <code>GTM</code> is dependent upon it.</p>