WP Travel customize

function travel_log_change_book_now_text(){

?>
    <script type="text/javascript"> 
       jQuery(function($) {

            $(window).load(function() {
                jQuery('#wp-travel-book-now').val('Book later');
            });

        } );
    </script>
<?php 
}

add_action('wp_footer', 'travel_log_change_book_now_text');