limit datepicker so past dates cannot be selected

/*
wpgenie.org

limit date picker so past dates cannot be selected, this JS code snippet should go to your child theme functions.php or customization plugin
https://wpgenie.org/tutorials-category/code-snippets-and-template-customizations-using-child-theme

*/

function wpgenie_limit_past_dates_in_datepicker() {
    ?>
    <script>
    jQuery(document).ready(function($) {
        jQuery('.datetimepicker').datetimepicker(
            {defaultDate: "",
            dateFormat: "yy-mm-dd",
            numberOfMonths: 1,
            showButtonPanel: true,
            minDate: new Date(),
            showOn: "button",
            buttonImage: SA_Ajax.calendar_image,
            buttonImageOnly: true
            });
    });
    </script>
    <?php
}
add_action( 'admin_head', 'wpgenie_limit_past_dates_in_datepicker' );   // loads JS in wp-admin / backend, comment line if not required in backend
add_action( 'wp_head', 'wpgenie_limit_past_dates_in_datepicker');       // loads JS in frontend, comment line if not required in frontend