Make the product category widget's sub categories hide on load

add_action('wp_head', 'fold_product_sub_cat', 11);
function fold_product_sub_cat(){
    ?>
    <script>
        jQuery(document).ready(function($){
            // make the sub categories hide on load
            $( "ul.children.level-0" ).css("display","none");
        });
    </script>
    <?php
}