How to Display Input Element on Dropdown Selection in Yii?

To display an input element on dropdown selection is very easy. We can follow below steps to achieve the goals-

By Using JavaScript:

Selection dropdown 1:

<div class="row">  
   <?php echo $form->labelEx($model,'status'); ?>

   <?php echo $form->dropDownList($model,'status',
      array('ON'=>'ON','OFF'=>'OFF'),
      array('onchange'=>'return checkStatus(this.value)'));

   <?php echo $form->error($model,'status'); ?>
</div>

Hidden div. Will active if selection is true

<div id="hiddendiv" style="display:none">                 
     <div class="row">
         <?php echo $form->labelEx($model,'category'); ?>
         <?php echo CHtml::activeDropDownList($model,'category', 
array('Book'=>'Book','Pen'=>'Pen'), 
array('prompt'=>'Select') ); ?>
         <?php echo $form->error($model,'category'); ?>
     </div>
</div>

function checkStatus(obj)
{
   if(obj=="ON")
   {
     document.getElementById('hiddendiv').style.display="block";
     return false;
   }
   else
   {
     document.getElementById('hiddendiv').style.display="none";
     return false;
   }
}

By Using Yii Ajax-

In View-

<div>
    <?php echo $form->labelEx($model,'status'); ?>

    <?php echo $form->dropDownList($model,'status',
        array('0' =>'In active', '1'=> 'Active'),

        array( 'onChange' => 'javascript:description()', 
                     'ajax'=>array(
                        'type'=>'POST',
                        'url'=>CController::createUrl('controllerName/functionName'),
                        'update'=>'#status_id',
        )));                         
        ?>
     <div id="status_id"></div>
     <?php echo $form->error($model,'status'); ?>
</div>

In Controller-

public function actionfunctionName()
{
    if($_POST['controllerName']['status']=="ON")
    {      
        //For only text field
        //echo CHtml::textField("Employment",'applying_position');

        // For Dropdownlist
        echo $form->dropDownList($model,'status',
        array('Book'=>'Book','Pen'=>'Pen'),
        array('prompt'=>'Select')
        );                         
    }
 }

Hope this will help!