在添加到购物车后，修改woocommerce中的插件以插入模态

I would like to create a modal box after click the add to cart button. But just if a checkbox is selected and inside an input there is a msg.

So I think the best way would be inside the function where the plugin, after the add to cart button is clicked, send the data to woocommerce.

Here it is the function

/**
     * When added to cart, save any gift wrap data
     *
     * @access public
     * @param mixed $cart_item_meta
     * @param mixed $product_id
     * @return void
     */
    public function add_cart_item_data ($cart_item_meta, $product_id ) {
        global $woocommerce;

        $is_wrappable = get_post_meta( $product_id, '_is_gift_wrappable', true );

        if ( $is_wrappable == '' && $this->gift_wrap_enabled )
            $is_wrappable = 'yes';

        if ( !empty( $_POST['gift_wrap'] ) && $is_wrappable == 'yes' )
            $cart_item_meta['gift_wrap'] = true;

        if ( !empty( $_POST['gift_wrap_selection'] ) && $is_wrappable == 'yes' )
            $cart_item_meta['gift_wrap_selection'] = strip_tags( $_POST['gift_wrap_selection'] );

        if ( !empty( $_POST['gift_wrap_inner_message'] ) && $is_wrappable == 'yes' ){

                        $cart_item_meta['gift_wrap_inner_message'] = strip_tags( $_POST['gift_wrap_inner_message'] );
                        }
        if ( !empty( $_POST['gift_wrap_outer_message'] ) && $is_wrappable == 'yes' )
            $cart_item_meta['gift_wrap_outer_message'] = strip_tags( $_POST['gift_wrap_outer_message'] );

        return $cart_item_meta;
    }

I think the best way is to call a function here:

if ( !empty( $_POST['gift_wrap_inner_message'] ) && $is_wrappable == 'yes' ){

                        $cart_item_meta['gift_wrap_inner_message'] = strip_tags( $_POST['gift_wrap_inner_message'] );
                        }