Open popup on click [Add to cart] - Woocommerce

In Woocommerce, i need to open a modal popup when the user clicks the Add to cart button. I tried this, but it doesn't work:

In functions.php:

if (is_woocommerce() && is_archive()) {
    wp_enqueue_script( 'frontend-custom', get_template_directory_uri() . '/js/frontend-custom.js', array("jquery"));
    add_thickbox();
}

In themedirectory/js/frontend-custom.js:

jQuery(document).ready(function($) {
    $('body').on('added_to_cart',function(e,data) {
        //alert('Added ' + data['div.widget_shopping_cart_content']);
        if ($('#hidden_cart').length == 0) { //add cart contents only once
            //$('.added_to_cart').after('<a href="#TB_inline?width=600&height=550&inlineId=hidden_cart" class="thickbox">View my inline content!</a>');
            $(this).append('<a href="#TB_inline?width=300&height=550&inlineId=hidden_cart" id="show_hidden_cart" title="<h2>Cart</h2>" class="thickbox" style="display:none"></a>');
            $(this).append('<div id="hidden_cart" style="display:none">'+data['div.widget_shopping_cart_content']+'</div>');
        }
        $('#show_hidden_cart').click();
    });
});

Any help appreciated.