Yii: return a variable from model to form with Ajax -

how change model send varibale model form ajax? want can happen in model in ( public function comp_group ) connect form. want model return $maxid _form.php

this _form.php

<?php /* @var $this textcontroller */ /* @var $model text */ /* @var $form cactiveform */ ?>  <div class="form">  <?php $form=$this->beginwidget('cactiveform', array(     'id'=>'text-form',     // please note: when enable ajax validation, make sure corresponding     // controller action handling ajax validation correctly.     // there call performajaxvalidation() commented in generated controller code.     // see class documentation of cactiveform details on this.     'enableajaxvalidation'=>true,      'focus'=>array($model,'group'),   //   'clientoptions'=>array(      //           'validateonchange'=>true,  // default. validate when input changes      //           'validateontype'=>'true',    // validate every keystroke, hooray!       //          'validationdelay'=>10,     // not related post--but cool!       //                                // default delay 200 ms     //    ), )); ?>      <p class="note">fields <span class="required">*</span> required.</p>      <?php echo $form->errorsummary($model); ?>      <div class="row">         <?php echo $form->labelex($model,'subject'); ?>         <?php echo $form->textfield($model,'subject',array('size'=>60,'maxlength'=>80)); ?>         <?php echo $form->error($model,'subject'); ?>     </div>      <div class="row">         <?php echo $form->labelex($model,'matn'); ?>         <?php echo $form->textfield($model,'matn',array('size'=>60,'maxlength'=>255)); ?>         <?php echo $form->error($model,'matn'); ?>     </div>      <div class="row">         <?php echo $form->labelex($model,'group'); ?>         <?php echo $form->textfield($model,'group',array('size'=>20,'maxlength'=>20)); ?>         <?php echo $form->error($model,'group'); ?>     </div> <?php $userx=yii::app()->session['idx']; ?>      <div class="row">         <?php // echo $form->labelex($model,'user_id'); ?>         <?php echo $form->textfield($model,'user_id',array ('value'=>$userx,'type'=>"hidden")); ?>         <?php // echo $form->error($model,'user_id'); ?>     </div>      <div class="row">         <?php echo $form->labelex($model,'privacy'); ?>         <?php echo $form->dropdownlist($model,'privacy',  array('1'=>'public','2'=>'only me')); ?>         <?php echo $form->error($model,'privacy'); ?>     </div>      <div class="row buttons">         <?php echo chtml::submitbutton($model->isnewrecord ? 'create' : 'save'); ?>     </div>  <?php $this->endwidget(); ?>  </div><!-- form --> <?php $sqlname='show columns `group`'; $gpnamet = yii::app()->db->createcommand($sqlname); $gpall =$gpnamet->queryall();  $sqlnumber="select count(*) information_schema.columns  table_name = 'group' "; $sqlnumberquery= yii::app()->db->createcommand($sqlnumber); $sqlnumberall=$sqlnumberquery->queryall(); $numbercolumns=( $sqlnumberall[0]['count(*)']);   ($t=1 ; $t<$numbercolumns ;$t++) { $columnsarray[]=($gpall[$t]['field']);  } print_r($columnsarray); //$mastercommand = yii::app()->db->createcommand();  ?> 

this model:

/**  * model class table "text".  *  * followings available columns in table 'text':  * @property integer $id  * @property string $subject  * @property string $matn  * @property string $group  * @property integer $user_id  * @property integer $privacy  *  * followings available model relations:  * @property users $user  */ class text extends cactiverecord {     /**      * @return string associated database table name      */     public function tablename()     {         return 'text';     }      /**      * @return array validation rules model attributes.      */     public function rules()     {         // note: should define rules attributes         // receive user inputs.         return array(             array('subject, user_id, privacy ,group', 'required'),             array('user_id, privacy', 'numerical', 'integeronly'=>true),             array('subject', 'length', 'max'=>80),             array('matn', 'length', 'max'=>255),             array('group', 'length', 'max'=>20 , 'min'=>2),                    array('group', 'comp_group'),              // following rule used search().             // @todo please remove attributes should not searched.             array('id, subject, matn, group, user_id, privacy', 'safe', 'on'=>'search'),         );     }              public function getidx()        {              $user= yii::app()->db->createcommand();    //     select users.username users inner join text  on text.user_id=users.id          //   select users.username users,  text  users.id=text.user_id;      $user = yii::app()->db->createcommand()     ->select('users.id')     ->from('users')     ->where('users.id=:username' , array(':username'=>1)) //    ->where('id=:id', array(':id'=>$id))     ->queryrow(); yii::app()->session['idx']=$user;     return $user;       }           /**      * @return array relational rules.      */     public function relations()     {         // note: may need adjust relation name , related         // class name relations automatically generated below.         return array(             'user' => array(self::belongs_to, 'users', 'user_id'),         );     }      /**      * @return array customized attribute labels (name=>label)      */     public function attributelabels()     {         return array(             'id' => 'id',             'subject' => 'subject',             'matn' => 'matn',             'group' => 'group',             'user_id' => 'user',             'privacy' => 'privacy',         );     }      /**      * retrieves list of models based on current search/filter conditions.      *      * typical usecase:      * - initialize model fields values filter form.      * - execute method cactivedataprovider instance filter      * models according data in model fields.      * - pass data provider cgridview, clistview or similar widget.      *      * @return cactivedataprovider data provider can return models      * based on search/filter conditions.      */     public function search()     {         // @todo please modify following code remove attributes should not searched.          $criteria=new cdbcriteria;          $criteria->compare('id',$this->id);         $criteria->compare('subject',$this->subject,true);         $criteria->compare('matn',$this->matn,true);         $criteria->compare('group',$this->group,true);         $criteria->compare('user_id',$this->user_id);         $criteria->compare('privacy',$this->privacy);          return new cactivedataprovider($this, array(             'criteria'=>$criteria,         ));     }      /**      * returns static model of specified ar class.      * please note should have exact method in cactiverecord descendants!      * @param string $classname active record class name.      * @return text static model class      */     public static function model($classname=__class__)     {         return parent::model($classname);     }                  public function comp_group($attributes , $params)       {   $sqlname='show columns `group`'; $gpnamet = yii::app()->db->createcommand($sqlname); $gpall =$gpnamet->queryall();  $sqlnumber="select count(*) information_schema.columns  table_name = 'group' "; $sqlnumberquery= yii::app()->db->createcommand($sqlnumber); $sqlnumberall=$sqlnumberquery->queryall(); $numbercolumns=( $sqlnumberall[0]['count(*)']);           ($t=1 ; $t<$numbercolumns ;$t++)             {                 $columnsarray[]=($gpall[$t]['field']);             } //print_r($columnsarray);            foreach ($columnsarray $u)           {               $mastercommand = yii::app()->db->createcommand();               $gname=$this->group;                  if($this->group == $u)               {                  $this->adderror('group' ," $gname registered");                  $mastercommand->reset();                  $mastercommand->insert('group',                           array                               (                   $this->group=>'1',                                 ));                  $maxid = $mastercommand->select('max(id)')->from('group')->queryall();                  $maxid=   $maxid[0]['max(id)'];                    break;               }                   else                     {                 $mastercommand->reset();                   $mastercommand->addcolumn('group' , $gname , 'int(1)');                 $mastercommand->reset();                  $mastercommand->insert('group', array(                   $this->group=>'1',                       ));           //    break;                      $maxid = $mastercommand->select('max(id)')->from('group')->queryall();                      $maxid=   $maxid[0]['max(id)'];                       }            }       } }