Yii add ajax loading indicator

Yii_ajax_loading_example.php

<?php

$this->widget('bootstrap.widgets.TbButton', array(
     'label'=>'<ButtonName>',
     'type'=>'ButtonType',
     'buttonType'=>'ajaxButton',
     'encodeLabel'=>true,
     'url'=>Yii::app()->createUrl('/<module>/<controller>/<action>'),
     'ajaxOptions'=>array(
        // Method - POST (for $_POST requests) or GET (for $_GET requests)
        'type'=>'<method>',
        // Data - that be send by ajax to controller action
        "data" => "<data>",
        // Selector for update
        'update'=>'#selector',
        // Function that be executed after ajax success
        'success' => "<success_function>",
        // Add loading class Before send ajax-request
        'beforeSend' => 'function(){        
            $("#<selector_loading>").addClass("ajax_loading");
         }',
        'complete' => 'function(){
            $("#selector_loading").removeClass("ajax_loading");
        }',
     ),
     'htmlOptions' => array(
        'onclick' => '
            var id_list_lock=$.fn.yiiGridView.getSelection("company-grid","ids");
                    if (id_list_lock=="") {
                        alert("Нет отмеченных записей!", "Alert Dialog");
                    }',
         'confirm' => 'Удалить выбранные записи?',
     ),     
     'type'=>null,
     'size'=>'small',
   ));  

// Also Need sleep(time_seconds); at the begin of controller/action

?>

<!-- CSS-styles -->

div.loading {
    background-color: #eee;
    background-image: url('loading.gif');
    background-position: center center;
    background-repeat: no-repeat;
    opacity: 1;
}
 
div.loading * {
    opacity: .8;
}