title: data-attribute in form tag
body: <p>I just stumbled upon a weird problem today, and asked myself if someone knew, what causes this?</p>
  
  <p>If I try to submit a form via jQuery and try to get a custom data-attribute, it will be "undefined".
  Here is the code to show you</p>
  
  <p>HTML</p>
  
  <pre><code>&lt;form action="/" method="POST" data-test="passed"&gt;
      &lt;input type="text" name="in1" value="valuable" /&gt;
      &lt;input type="submit" /&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>JS</p>
  
  <pre><code>$(function(){
      $('form').submit(function(){
  
         // this will work
         alert(this.action);
  
         // this will fail
         alert(this.data-test);
  
         return false;
     });
  });
  </code></pre>
  
  <p>JSFiddle: <a href="http://jsfiddle.net/7etzas0m/" rel="nofollow">http://jsfiddle.net/7etzas0m/</a></p>
  
  <p>I hope someone is interested, and can answer my question.
  Thanks</p>