title: .data() not returning undefined
body: <p>I trying to use .data to get a value out of an attribute.</p>
  
  <p>HTML</p>
  
  <pre><code>&lt;div class="like" data-postid="903282304865jh"&gt; &lt;/div&gt;
  </code></pre>
  
  <p>JS</p>
  
  <pre><code>$(".like").click(function(event){ 
        var postID = $(event.target).data('postid');
        console.log(postID);
  });
  </code></pre>
  
  <p>I get undefined returned in my console. Whats going on here? </p>