Yii Cgridview Search Issue

Yii CGridView filtering is working but search not working so what would be miss , can u help me to sort out this issue my code attach bellow

#########grid.php ######################


<?php

//grid ajax search

Yii::app()->clientScript->registerScript('search', "

$('.search-button').click(function(){

	$('.search-form').toggle();

	return false;

});

$('.search-form form').submit(function(){

	$.fn.yiiGridView.update('coupon-grid', {

		data: $(this).serialize()

	});

	return false;

});

");


//set page size for data provider

$dp = $coupons->search();

$dp->pagination->pageSize = 25;

$this->widget('zii.widgets.grid.CGridView', array(

    'id'=>'coupon-grid',

    'dataProvider'=>$dp,

       'columns'=>array(        

        array(

            'name'=>'AdvertisementName',

            'type'=>'raw',

            'value'=>'CHtml::link(CHtml::encode($data->offer_title), array("create", "id"=>$data->id))',            

        ),

        array(

            'name'=>'store_name',

            'value'=>'$data->store_name',

        ),

        array(

            'name'=>'Vendor',

            'value'=>'$data->vendor->description',

        ),         

        'exp_date:text:Expiration Date',

        /*array(

            'name'=>'CreatedBy',

            'value'=>'$data->user->name',

        ),  */      

        'status:text:Status'

    ),

    'cssFile'=>false

));

?>

index.php

<script type="text/javascript">

    $(function() {

        $("#Coupon_created_date").datepicker({dateFormat: 'yy-mm-dd'});


    });

</script>

<div>

    <table cellpadding="0" cellspacing="0" border="0" width="100%">

        <tr>

            <td class="tab-content-left ver-bg"></td>

            <td  class="tab-content">

                <?php

                $form = $this->beginWidget('CActiveForm', array(

                    'action' => Yii::app()->createUrl($this->route),

                    'method' => 'get',

                ));

                ?>

                <div class="row container-1">

                    <div class="inner-frame">


                        <table cellpadding="0"  class="tbl-form" cellspacing="0" border="0" width="100%">

                            <tr>

                                <td width="160" class="bold-text" >Offer Title:</td>

                                <td width="200"><?php echo CHtml::activeTextField($coupons, 'offer_title', array('class' => 'txt-common')) ?></td>

                                <td width="35"></td>

                                <td width="160" class="bold-text" >Status:</td>

                                <td><?php echo CHtml::activeTextField($coupons, 'status', array('class' => 'txt-common')) ?></td>

                            </tr>


                            <tr>

                                <td class="bold-text" >Category:</td>

                                <td ><?php echo CHtml::dropDownList('catogary_id', $categoryId, CHtml::listData($catogaries, 'id', 'name'), array('empty' => '- - Select - -')); ?></td>

                                <td ></td>

                                <td class="bold-text" >Created By:</td>

                                <td><?php echo CHtml::activeDropDownList($coupons, 'created_by', CHtml::listData($users, 'id', 'name'), array('empty' => '- - Select - -')); ?></td>

                            </tr>

                            <tr class="last">


                                <td  class="bold-text" >Created Date:</td>

                                <td ><?php echo CHtml::activeTextField($coupons, 'created_date', array('class' => 'txt-common')) ?></td>

                                <td ></td>

                                <td class="bold-text">Store Name</td>

                                <td><?php echo CHtml::activeTextField($coupons, 'store_name', array('class' => 'txt-common')) ?></td>

                            </tr>

                        </table>

                    </div>

                </div>

                <div class="row">

                    <?php echo CHtml::submitButton('Search', array('id' => 'search_btn', 'class' => 'btn hor-bg', 'name' => 'Search')); ?>

                    <?php echo CHtml::submitButton('Clear Search Fields', array('id' => 'search_clear_btn', 'class' => 'btn hor-bg', 'name' => 'Clear')); ?>

                </div>

                <?php $this->endWidget(); ?>

                <div class="row">

                    <div class="grid-title">

                        <div class="inner-bdr"> <span class="float-left bold-text">Advertisement List</span>




                            <div class="clear-both"></div>

                        </div>

                        <div class="grid-bg">

                            <div class="grid-bg-inner-bdr">


                                <?php echo $this->renderPartial('grid', array('coupons' => $coupons)); ?>


                            </div>


                        </div>

                    </div>

                </div>

                <div class="">

                    <input type="button" onclick="goTo('<?php echo Yii::app()->params['hostname'] . '/index.php/admin/coupon/create' ?>')" class="btn hor-bg" value="Add New Advertisement" />

                    <input type="button" onclick="goTo('<?php echo Yii::app()->params['hostname'] . '/index.php/admin/coupon/review' ?>')" class="btn hor-bg" value="Edit Advertisements" />

                </div>

            </td>

            <td class="tab-content-right ver-bg"></td>

        </tr>


    </table>

</div>




####### model search action ##########################


 public function search() {

      // Warning: Please modify the following code to remove attributes that

      // should not be searched.

      $sort = new CSort();

      $sort->attributes = array('AdvertisementName'=>array('asc'=>'offer_title', 'desc'=>'offer_title desc',),

          'store_name'=>array('asc'=>'store_name', 'desc'=>'store_name desc',),

          'exp_date'=>array('asc'=>'exp_date', 'desc'=>'exp_date desc',),

          'status'=>array('asc'=>'t.status', 'desc'=>'t.status desc',),

          'CreatedBy'=>array('asc'=>'user.name', 'desc'=>'user.name desc',),

          'Vendor'=>array('asc'=>'vendor.description', 'desc'=>'vendor.description desc',),

      );

     

      $criteria = new CDbCriteria;

      $criteria->with = array('vendor', 'user');

      if (!empty($this->subCategoryIdsAr) && is_array($this->subCategoryIdsAr)) {

         foreach ($this->subCategoryIdsAr as $subcategoryId) {


            $criteria->compare('sub_category_id', $subcategoryId->id, true, 'OR');

         }

      }


      $criteria->compare('id', $this->id, true);

      $criteria->compare('t.created_date', $this->created_date, true);

      $criteria->compare('offer_title', $this->offer_title, true);

      $criteria->compare('t.created_by', $this->created_by, true);

      $criteria->compare('t.status', $this->status, true);

      $criteria->compare('t.store_name', $this->store_name, true);

      return new CActiveDataProvider(get_class($this), array(

          'criteria'=>$criteria,

          'sort'=>$sort,

      ));

   }

######## IndexAction,php #########################


<?php


/**

 * LoginAction class file

 *

 * @author Gayan

 * @copyright Copyright&copy; 2011 SoNET Systems

 */


/**

 * Used to hanle login functinality

 *

 * @package am.admin.Dashboard

 */

class IndexAction extends CAction {


   public function run() {

      $controller = $this->getController();

      $categoryId = '';

      //create models for view

      $coupons = new Coupon();

      $users = User::model()->findAll();

      $catogaries = Category::model()->findAll();

      foreach ($catogaries as $category) {

         $category->name = ucfirst($category->name);

      }


      if (isset($_POST['Clear'])) {

         unset($_POST);

         Yii::app()->user->setState('searchFields', '');

      }

      

      if (isset($_POST['Coupon'])) {           

         if (isset($_POST['catogary_id']) && !empty($_POST['catogary_id']))

            $categoryId = $_POST['catogary_id'];

         $coupons->getSubCategories((int) $categoryId);

         $coupons->attributes = $_POST['Coupon'];

         $coupons->setStateAttributes(); //set searching fields to state for ajax pagination

      }


      //if (Yii::app()->request->isAjaxRequest) {

         $coupons->attributes = Yii::app()->user->getState('searchFields');

      //}


      $params = array(

          'coupons'=>$coupons,

          'users'=>$users,

          'catogaries'=>$catogaries,

          'categoryId'=>$categoryId

      );

      $controller->render('index', $params);

   }

}



plz help me to solve this issue?

can u plz any one help me