title: Bind Vue on body or others element
body: <p>I've seen many times Vue instance is bind on <code>body</code> tag.
  Other times this is bind on a <code>div id</code></p>
  
  <p>I'm asking when i should use <code>body</code> tag or an <code>id</code> tag (that limit the scope of the Vue instance).</p>
  
  <p>Two examples:</p>
  
  <pre><code>new Vue({
    el: 'body'
  });
  </code></pre>
  
  <p>OR</p>
  
  <pre><code>new Vue({
    el: '#a-div'
  });
  </code></pre>