title: What is role="listbox" used when creating carousel?
body: <p>Just a simple question</p>
  
  <p>When I tried to create a carousel, I noticed many sample codes are:</p>
  
  <pre><code>&lt;div class="carousel-inner" role="listbox"&gt;
  </code></pre>
  
  <p>In the above code, what does <strong>role="listbox"</strong> do?
  Please give me an insight.</p>