How to add Custom Validation for select box?

At Widget : 

## define unique form input names :

#set ($persona = $core_v2_widget.UniqueId('persona'))

<script type="text/javascript">
//<![CDATA[
jQuery(document).ready(function(j){

j.microsoft.dynamics.widgets.userCreate.register({
wrapper: '#$core_v2_encoding.JavascriptEncode(${core_v2_widget.WrapperElementId})',
inputs: {
persona: "#$core_v2_encoding.JavascriptEncode($persona)",
},

resources: {
personaInvaild: "$core_v2_encoding.JavascriptEncode($core_v2_language.GetResource('CreateNewAccount_InvalidPersona'))"
},

At .vm File : 

<div class="form-group field-item required persona">
<label class="meta-large" for="$core_v2_encoding.HtmlAttributeEncode($persona)">$core_v2_language.GetResource('CreateNewAccount_Persona')</label><span class="field-item-validation" title="$core_v2_language.GetResource('RequiredTitleText')">*</span><br/>
<select name="persona" id="$core_v2_encoding.HtmlAttributeEncode($persona)">
<option value="">Select Profession</option>
<option value="IT Professional">IT Professional</option>
<option value="CFO">CFO</option>
</select>
</div>

At ui.js:

context.inputs.persona.live('change', function () {
context.elements.createAccountLink.evolutionValidation('validate');
});

if(context.inputs.persona.value != "") {
//alert("alert");
context.elements.createAccountLink.evolutionValidation('addField',
context.inputs.persona,
{
required: true,
persona: true,
messages: {
persona: context.resources.personaInvaild,
required: context.resources.fieldRequired
}
},
context.inputs.persona.closest('.field-item').find('.field-item-validation'), null);
}

There is some issue when we are selecting any option from select box, the code in ui.js is not working. Kindly Suggest how we can solve this issue.

Thanks