title: HTML5 Doctype tag and HTML tag together in HTML file
body: <p>I am aware about  declaration at top of HTML file.</p>
  
  <p>But I have seen code is something like :</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;    **Is it necessary to write after already declaring &lt;!DOCTYPE HTML&gt;**
  &lt;head&gt;
  &lt;title&gt;Title of the document&lt;/title&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
   The content of the document......
  &lt;/body&gt;
  &lt;/html&gt; 
  </code></pre>
  
  <p>I just want to comfirm standard to declare HTML5 declaration wheather standalone HTML tag is mandatory to declare after declaring DOCTYPE HTML at top ? </p>
  
  <p>Thanks </p>