title: This code should show error as there is extra tag than dtd. But it's not showing any error. What's the fault?
body: <p>This code should show error as there is extra tag than dtd. But it's not showing any error. What's the fault?</p>
  
     
  
  <pre><code>&lt;!DOCTYPE emaildetails [
      &lt;!ELEMENT email ( to, from, subject, body )&gt;
      &lt;!ELEMENT to ( #PCDATA )&gt;
      &lt;!ELEMENT from ( #PCDATA )&gt;
      &lt;!ELEMENT subject ( #PCDATA )&gt;
      &lt;!ELEMENT body ( #PCDATA )&gt;
      ]&gt;
  
  
  &lt;emaildetails&gt;
  &lt;email&gt;
      &lt;to&gt;abc@gmail.com&lt;/to&gt;
      &lt;from&gt;xyz@gmail.com&lt;/from&gt;
      &lt;subject&gt;Hello&lt;/subject&gt;
      &lt;help&gt;me&lt;/help&gt;
      &lt;body&gt;How are you?&lt;/body&gt;
  &lt;/email&gt;
  &lt;email&gt;
      &lt;to&gt;mno@gmail.com&lt;/to&gt;
      &lt;from&gt;xyz@gmail.com&lt;/from&gt;
      &lt;subject&gt;Good&lt;/subject&gt;
      &lt;body&gt;I am fine&lt;/body&gt;
      &lt;help&gt;Me&lt;/help&gt;
  &lt;/email&gt;
  &lt;/emaildetails&gt;
  </code></pre>