title: How to set class="active" in jquery
body: <p>I have a sample code:</p>
  
  <pre><code>&lt;div class="box"&gt;
          &lt;div id="banks"&gt;
              &lt;ul&gt;
                  &lt;li class="active1"&gt;Bank1&lt;/li&gt;
                  &lt;li"&gt;Bank2&lt;/li&gt;
              &lt;/ul&gt;
          &lt;/div&gt;
          &lt;div id="buttons"&gt;
              &lt;ul&gt;
                  &lt;li class="active2"&gt;USD&lt;/li&gt;
                  &lt;li&gt;EURO&lt;/li&gt;
              &lt;/ul&gt;        
          &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>And jquery:</p>
  
  <pre><code>&lt;script&gt;
  $(document).ready(function(){
      $('.box li').click(function(){
          $('#banks li').removeClass('active1');
          $('#buttons li').removeClass('active2');
          $(this).addClass('active1');
          $(this).addClass('active2');
      });    
  });
  &lt;/script&gt;
  </code></pre>
  
  <p>OUPUT: Error when click on:</p>
  
  <pre><code>&lt;div class="box"&gt;
          &lt;div id="banks"&gt;
              &lt;ul&gt;
                  &lt;li class="active2 active1"&gt;Bank1&lt;/li&gt;
                  &lt;li class="active2"&gt;Bank2&lt;/li&gt;
              &lt;/ul&gt;
          &lt;/div&gt;
          &lt;div id="buttons"&gt;
              &lt;ul&gt;
                  &lt;li class=""&gt;USD&lt;/li&gt;
                  &lt;li class=""&gt;EURO&lt;/li&gt;
              &lt;/ul&gt;        
          &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>How to using jquery exactly for add class for 2 id are (banks and buttons) with 2 class are (active1, active2)</p>