title: Select multiple element not empty validation engine without required
body: <p>I need to do validation that at least one element is selected. This element was filled dynamically and I need to validate if that I have at least one option element selected, using validation Engine.</p>
  
  <p>Here fill the select option item</p>
  
  <pre><code>jQuery("#bt_add").click(function(){
      storeUsedGroups[attr_group.val()] = true;
  
      jQuery("#atributo_id").append('&lt;option value='+attr_name.val() + 
          ' groupid='+attr_group.val()+'&gt;' + attr_group.text() + 
          ' : ' + attr_name.text()+'&lt;/option&gt;'
      );
  });
  </code></pre>
  
  <p>and validate with required, but for submit form need select the options inserted.</p>
  
  <pre><code>&lt;select name="atributo_id[]" id="atributo_id" multiple="multiple" class="validate[required]"&gt;
      &lt;option value="5" groupid="1"&gt;Color : Azul&lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>I just need to validate non-empty the element.</p>