title: Adding class to element with matching custom data attribute
body: <p>I have a list of elements with Custom Data Attributes. I need to be able to add a class to another element on click when the data attribute of a clicked element matches the data attribute of that element.</p>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>&lt;div data-my-element="value1"&gt;click 1&lt;/div&gt;  
  &lt;div data-my-element="another"&gt;click 2&lt;/div&gt; 
  &lt;div data-my-element="oneMore"&gt;click 3&lt;/div&gt; 
  
  &lt;section data-my-element="value1"&gt;&lt;/section&gt;
  &lt;section data-my-element="another"&gt;&lt;/section&gt;
  &lt;section data-my-element="oneMore"&gt;&lt;/section&gt;
  </code></pre>
  
  <p><strong>JS</strong></p>
  
  <pre><code>$('div').click(function() {
      var myEm = $(this).val('data-my-element');
      $('section[data-my-element = '+myEm+']').addClass('clicked');
  });
  </code></pre>
  
  <p>I think I'm doing something wrong.</p>
  
  <p><a href="http://jsfiddle.net/wEgLp/" rel="noreferrer">FIDDLE</a></p>