public function getSubCatsAction($params){
        $parentCatId = $this->getRequest()->getPost();
        $parentCat = Mage::getModel('catalog/category')->load($parentCatId['id']);
        $allChildren = $parentCat->getAllChildren();
        $allChildren = explode(',', $allChildren);
        //var_dump($allChildren);
        $subCategories = Mage::getModel('catalog/category')->getCollection()
            ->addAttributeToSelect('*')
            ->addAttributeToFilter('include_in_menu','1')
            ->addAttributeToFilter('is_active','1')
            ->addAttributeToFilter('entity_id', array('in' => $allChildren));
$text = '<select id="search-field-sub-category" name="search-field-sub-category">';
        foreach($subCategories as $subCat){
            if($parentCatId['id'] != $subCat->getId()){
                $text.='<option value="'.$subCat->getId().'">'.$subCat->getName().'('.$subCat->getDynamicProductsCount().')'."</option>";
            }
            else if($parentCatId['id'] == $subCat->getId()){
                $text.='<option value="'.$subCat->getId().'"> All '.$subCat->getName().' ('.$subCat->getDynamicProductsCount().')'."</option>";
            }
        }
        $text.= '</select>';


$this->getResponse()->setHeader('Content-type', 'application/json',true);
        $this->getResponse()->setBody(json_encode($text));

    }