title: event.target.classList doesn't have indexOf method
body: <pre><code>&lt;script src="jquery.js"&gt;&lt;/script&gt;
  &lt;button class="hello bello jello"&gt;start text&lt;/button&gt;
  &lt;script&gt;
  $("button").on("click", function(event) {
      var lo = event.target.classList
      console.log(lo.indexOf("hello"))
  })
  &lt;/script&gt;
  </code></pre>
  
  <p>I expected the above snippet to print, <code>0</code> but it threw out an error <code>lo.indexOf is not a function</code>.</p>
  
  <p>Isn't event.target.classList typed as array?</p>