获取列表的顺序并发布php

Question

我想要一个HTML列表，用户可以通过拖放操作重新排序（我已经这样做了）

然后我想获取当前订单并在按钮单击时用php发布

JS

jQuery(document).ready(function(){
    jQuery("#new_fields").sortable({
        cursor:'move',
        // post
        update:function(){
            var order=jQuery('#new_fields').sortable('serialize');
            jQuery.ajax({
                type: "POST",
                url: "<?php bloginfo( 'myurl' ); ?>/wp-admin/admin-ajax.php",
                data: "action=update_field_order&" + order
            });
        }});
    jQuery("#new_fields").disableSelection();

    var ul = document.querySelector('ul');
    for (var i = ul.children.length; i >= 0; i--) {
        ul.appendChild(ul.children[Math.random() * i | 0]);
    }

});

php

<div class="wrap">
    <div id="primary" class="content-area">
        <main id="main" class="site-main" role="main">

            <?php
            while ( have_posts() ) :
                the_post();

                get_template_part( 'template-parts/page/content', 'page' );

                // If comments are open or we have at least one comment, load up the comment template.
                if ( comments_open() || get_comments_number() ) :
                    comments_template();
                endif;

            endwhile; // End of the loop.
            ?>


        </main><!-- #main -->
    </div><!-- #primary -->
</div><!-- .wrap -->

<?php
function updateFilmOrder(){
    global $wpdb;
    foreach ($_POST['field_id'] as $position => $item)
        $wpdb->query("UPDATE table_name SET list_order='{$position}' where id=$item");
    die();
}
add_action('wp_ajax_update_field_order', 'update_field_order' );
?>
    <form action="welcome_get.php" method="get">
        Name: <input type="text" name="name"><br>
        E-mail: <input type="text" name="email"><br>
        <input type="submit">
    </form>

和HTML（ul）

   <h2>Place the .....</h2>
<ul id="new_fields">
   <li id="field_id_1" class="ui-state-default">The Abyss</li>
   <li id="field_id_2" class="ui-state-default">Aliens</li>
   <li id="field_id_3" class="ui-state-default">The Terminator</li>
  <li id="field_id_4" class="ui-state-default">Terminator 2: Judgement Day</li>
<li id="field_id_5" class="ui-state-default">Avatar</li>
<li id="field_id_6" class="ui-state-default">Titanic</li>
<li id="field_id_7" class="ui-state-default">Piranha II: The Spawning</li>
</ul>

我需要知道如何获取订单以及如何发布