Can't catch a data in a custom module via AJAX get request

Code: Select all

<script>
     $('#category').on('change', function() { //#category is an id for <select> list with categories
            $.ajax({
                method: 'GET',
                url: 'index.php?route=module/my_module&category_id='+this.value, //here i set up a url to controller and parameter for get query

            }).done(function(data, Status){

            });
      });
</script>

Code: Select all

$this->load->model('catalog/product');
        $category_id = $this->request->get['category_id']; //here i try to catch the get data but it can't
        $this->data['product'] = $this->model_catalog_product->getProductsByCategoryId($category_id);

        $this->response->setOutput();