How Can I Get Dropdown List Value Inside The Form Through Ajax

i want to get the drop down list value inside the form but it always give 0 what is the problem here

here is my code i have enabled ajax

it always display "select"




<div class="row">

<tr>

<th>

<?php echo $form->labelEx($model,'Merchant or Brand',array('style'=>'display:inline','margin-left'=>"20px")); ?>

</th>

<td>

<?php echo CHtml::activeDropDownList($model,'merchant',Merchant::model()->Merchant,array('id'=>'merchant')); ?>

</td>

</tr>

<tr id="merchantcity">

	<td></td>

	<td>

		<?php 

			if($model->merchant==0)

				echo "select";

			else

				echo "other";

		?>

	</td>

</tr>


</div>