title: On keydown trigger next tab index (focus next element)
body: <p>I am having a bootstrap's dropdown menu (I implemented only styles without Javascript)... hence I need to port to angular2 some js functionality.</p>
  
  <p>One is keyboard accessibility.</p>
  
  <p>So far I have:</p>
  
  <pre><code>&lt;div (keydown)="onMenuKeydown($event)" ....&gt;
      &lt;ul class="dropdown-menu"&gt;
          &lt;li&gt;&lt;a href="#"...&gt;option 1&lt;/a&gt;&lt;/li&gt;
          &lt;li&gt;&lt;a href="#"...&gt;option 2&lt;/a&gt;&lt;/li&gt;
          &lt;li&gt;&lt;a href="#"...&gt;option 3&lt;/a&gt;&lt;/li&gt;
      &lt;/ul&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>In my controller I have this:</p>
  
  <pre><code>onMenuKeydown(event: KeyboardEvent){
      if(event.keyCode === 40){
          /*event.srcElement.nextSibling.*/
          event.preventDefault();
      }
  }
  </code></pre>
  
  <p>What I would like is that on arrow down it simulates or triggers the TAB key (so it should focus next element) and on arrow key up to simulate the SHIFT-TAB key (previous tabindex)</p>
  
  <p>I have the <code>event.srcElement</code> and have <code>nextSibling</code>property but it doesn't have the method focus... so cannot do <code>event.srcElement.nextSibling.focus();</code>.</p>
  
  <p>What would be the best solution here?</p>