title: How to call Struts 2 client-side validation using theme="simple"?
body: <p>When applying <strong><code>theme="simple"</code></strong> to my Struts 2 form tag, the JavaScript <code>validateForm_&lt;formName&gt;</code> function isn't "generated" anymore.</p>
  
  <h3>With the simple theme</h3>
  
  <p>The form tag :</p>
  
  <pre><code>&lt;s:form id="editForm" validate="true" action="Edit" namespace="/ValidationTest" theme="simple"&gt;
  </code></pre>
  
  <p>From JavaScript console :</p>
  
  <pre><code>&gt; validateForm_editForm()
  ReferenceError: validateForm_editForm is not defined
  </code></pre>
  
  <h3>Without the simple theme</h3>
  
  <p>It works fine without the theme (so I assume that XML validation files and other configuration are correct) :</p>
  
  <pre><code>&lt;s:form id="editForm" validate="true" action="Edit" namespace="/ValidationTest"&gt;
  </code></pre>
  
  <p>JS console :</p>
  
  <pre><code>&gt; validateForm_editForm()
  false
  </code></pre>
  
  <hr>
  
  <p>I don't know if it's important but the <code>&lt;s:head /&gt;</code> tag is present :</p>
  
  <pre><code>&lt;head&gt;
      ...
      &lt;s:head /&gt;
  &lt;/head&gt;
  </code></pre>
  
  <hr>
  
  <ul>
  <li><strong>Is there something specific to include in order for Struts to generate the <code>validateForm_&lt;formName&gt;</code> function (similar to adding <code>&lt;s:fielderror /&gt;</code> tags with the simple theme) ?</strong></li>
  <li>I cannot find any "official" documentation and reference to this autogenerated JS function, mainly because its name is dynamic.</li>
  </ul>