yii ajax depedent dropdown issue - php

Question

i am working on ajax dependent dropdown its working fine but one issue is there ,the dropdownn which is dependendent on another dropdown has a prompt ----- "select".but when the parent dropdown is selected the prompt in dependent dropdown disapppears and is filled with the related data,i want that the prompt should be present there and user should select from dropdown.
right now by difault first data is selected
view form code
<div class="row">
php echo $form->labelEx($model, 'quarter'); ?>
<?php
$options = array(1 => 'First', 2 => 'Second', 3 => 'Third', 4 => 'Fourth');
$curMonth = date("m", time());
$curQuarter = ceil($curMonth/3);
$qr = array();
$qr[$curQuarter] = $options[$curQuarter];
$qr[$curQuarter-1] = $options[$curQuarter-1];
echo $form->dropDownList($model, 'quarter', $qr,array(
'prompt' => 'Select a quarter',
ajax' => array(
'type' => 'POST',
'url' => Yii::app()->controller->createUrl('dynamicProjectUserRoles'),
'update' => '#A2fs_role_id'
)
)) ?>
<?php echo $form->error($model, 'quarter'); ?>
</div>
<div class="row">
<?php echo $form->labelEx($model, 'role_id'); ?>
<?php echo $form->dropDownList($model, 'role_id', array(),array(
'prompt' => 'Select a role',
'ajax' =>array(
'type' => 'POST',
'url' => Yii::app()->controller->createUrl('questions'),
'update' => '#ques'
)
)); ?>
<?php echo $form->error($model, 'role_id'); ?>
</div>
// Controller code
public function actionDynamicProjectUserRoles() {
$project_id = $_POST['A2fs']['project_id'];
$quarter = $_POST['A2fs']['quarter'];
$employee = $_POST['A2fs']['employee_id'];
//$this->pr($project_id);
$id = $this->getEmployeeId($employee);
$conditon = $this->getQuarterDate($quarter);
// find roles of partcular employee
$q = "SELECT role_id FROM employee_project_role WHERE employee_id=$id AND project_id = $project_id and $conditon ";
$cmd = Yii::app()->db->createCommand($q);
//$result = $cmd->queryRow();
$role = $cmd->queryAll();
foreach ($role as $r){
$criteria = new CDbCriteria();
$criteria = array(
'select' => 'role',
'condition' => 'id=:id',
'params' => array(
':id' => $r['role_id']
)
);
$name = Role::model()->find($criteria);
echo CHtml::tag('option',
array(),CHtml::encode($name->role),true);
}
}

Answer 1

This is how it works - it renders the whole element by given ID. Just add
echo CHtml::tag('option', array('value' => ''), 'Select a role', true);
before
foreach ($role as $r){
in controller file.