title: How to alert using jQuery
body: <p>This works:</p>
  
  <pre><code>$('.overdue').addClass('alert');
  </code></pre>
  
  <p>But this doesn't:</p>
  
  <pre><code>$('.overdue').alert('Your book is overdue.'); 
  </code></pre>
  
  <p>What is the correct jQuery syntax for: </p>
  
  <pre><code>FOR EACH CLASS="overdue"
     alert('Your book is overdue');
  NEXT
  </code></pre>