title: How implement a "observer" in Jquery without plugins?
body: <p>I need a implementation of <a href="http://www.prototypejs.org/api/event/observe" rel="nofollow">http://www.prototypejs.org/api/event/observe</a> in Jquery?
  With <strong>"frequency</strong>" too?</p>
  
  <p>I need to a ticket for cakephp.</p>
  
  <p>Thanks,
  Celso.</p>