title: Zend Framework. How to add extra class to label
body: <p>My problem is after the form has been generated, the label class has assigned to a default which is optional and the html code looks like this:</p>
  
  <pre><code>&lt;div class="form_wrapper"&gt;
      &lt;label for="email" class="optional"&gt;Username(e-mail):&lt;/label&gt;
      &lt;input type="text" name="email" id="email" value=""&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>My zend code inside action is:</p>
  
  <pre><code>$form-&gt;addElement('text', 'email');
  $usernameElement = $form-&gt;getElement('email');
  $usernameElement-&gt;setLabel('Username(e-mail):');
  $usernameElement-&gt;setDecorators(array(
      'ViewHelper',
      'Label',
      new Zend_Form_Decorator_HtmlTag(array('tag' =&gt; 'div','class'=&gt;'form_wrapper')) 
  ));
  </code></pre>
  
  <p>But in some case, I want it to be set as a different value that I can easily style in css. The html code I want is this(get rid of "optional"):</p>
  
  <pre><code>&lt;div class="form_wrapper"&gt;
      &lt;label for="email" class="email_label"&gt;Username(e-mail):&lt;/label&gt;
      &lt;input type="text" name="email" id="email" value=""&gt;
  &lt;/div&gt;
  </code></pre>