title: Why we cannot provide ID(#) selector in Angular 2 directive
body: <p>We can create directives using following selectors in Angular 2</p>
  
  <ol>
  <li>Property:  <code>selector:'[myDir]'</code><br>
    Consumption:  <code>&lt;h1 myDir&gt;&lt;/h1&gt;</code></li>
  <li>Class:  <code>selector:'.myDir'</code>
    Consumption:  <code>&lt;h1 class="myDir"&gt;&lt;/h1&gt;</code></li>
  <li>Element:  <code>selector:'myDir'</code><br>
    Consumption:  <code>&lt;myDir&gt;&lt;/myDir&gt;</code></li>
  </ol>
  
  <p>Then why we cannot create directives using Id (#)</p>
  
  <pre><code>  selector : '#myDir'
  </code></pre>