title: How can I select an element with multiple classes in jQuery?
body: <p>I want to select all the elements that have the two classes <code>a</code> and <code>b</code>.</p>
  
  <pre><code>&lt;element class="a b"&gt;
  </code></pre>
  
  <p>So, only the elements that have <em>both</em> classes.</p>
  
  <p>When I use <code>$(".a, .b")</code> it gives me the union, but I want the intersection.</p>