title: Add event to dynamically generated element
body: <p>How can I add an event to an element which was loaded by AJAX.</p>
  
  <p>jQuery has <code>live</code>, but what's the Mootools equivalent?</p>
  
  <p>For example:</p>
  
  <pre><code>window.addEvent('domready', function() {
      // some code which loads new elements by ajax
  
      // Filter
      $$('.filterButton').addEvent('click', function(event) {
          alert('wow');
      });
  });
  </code></pre>