title: Hide everything comes outside form tag
body: <p>My HTML structure is like this</p>
  
  <pre><code> &lt;body&gt;
      &lt;form&gt;&lt;/form&gt;
      &lt;div&gt;&lt;/div&gt;
      &lt;center&gt;&lt;/center&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p>I want to hide everything outside  &lt;<code>form&gt;&lt;/form&gt;</code> using  css or javascript. means output will be something like this</p>
  
  <pre><code>&lt;body&gt;
      &lt;form&gt;&lt;/form&gt;
      &lt;div style="display: none"&gt;&lt;/div&gt;
      &lt;center style="display: none"&gt;&lt;/center&gt;
  &lt;/body&gt;
  </code></pre>
  
  <p>I will prefer CSS as it can take over the case before dom loads.</p>