使用Selectize填充第二个下拉列表

Question

我正在使用Chosen插件根据第一个选择填充第二个下拉列表。我现在想出于性能原因切换到Selectize插件，但是我很难这样做。我的设置如下：

第一次下拉=自定义帖子类型（类型）

第二次下拉=分类（位置）

在我的functions.php文件中，我有以下内容：

// SECOND DROPDOWN

function my_dropdown_categories( $taxonomy, $current_selected = '', $include = null ) {
// Get all terms of the chosen taxonomy
$terms = get_terms($taxonomy, array('orderby' => 'name'));

// our content variable
$list_of_terms = '<select id="location"  class="selectboxSingle" name="location">';

if ( ! is_wp_error( $terms ) ) foreach($terms as $term){

    // If include array set, exclude unless in array.
    if ( is_array( $include ) && ! in_array( $term->slug, $include ) ) continue;

    $select = ($current_selected == $term->slug) ? "selected" : ""; // Note: ==

    if ($term->parent == 0 ) {

        // get children of current parent.
        $tchildren = get_term_children($term->term_id, $taxonomy);

        $children = array();
        foreach ($tchildren as $child) {
            $cterm = get_term_by( 'id', $child, $taxonomy );
            // If include array set, exclude unless in array.
            if ( is_array( $include ) && ! in_array( $cterm->slug, $include ) ) continue;
            $children[$cterm->name] = $cterm;
        }
        ksort($children);

        // OPTGROUP FOR PARENTS
        if (count($children) > 0 ) {
        //     $list_of_terms .= '<optgroup label="'. $term->name .'">';
             if ($term->count > 0)
                 $list_of_terms .= '<option class ="group-result" value="'.$term->slug.'" '.$select.'>' . $term->name .' </option>';
        } else
            $list_of_terms .= '<option value="'.$term->slug.'" '.$select.'>'. $term->name .' </option>';
        //$i++;

        // now the CHILDREN.
        foreach($children as $child) {
             $select = ($current_selected == $child->slug) ? "selected" : ""; // Note: child, not cterm
             $list_of_terms .= '<option value="'.$child->slug.'" '.$select.'>'. $child->name.' </option>';

        } //end foreach

        if (count($children) > 0 ) {
            $list_of_terms .= "</optgroup>";
        }
    }
}

$list_of_terms .= '</select>';

return $list_of_terms;
}

// FIRST DROPDOWN

add_action( 'wp_ajax_wpse158929_get_terms_for_cpt', 'wpse158929_get_terms_for_cpt' );
add_action( 'wp_ajax_nopriv_wpse158929_get_terms_for_cpt', 'wpse158929_get_terms_for_cpt' );

function wpse158929_get_terms_for_cpt() {
$ret = array( 'html' => '', 'error' => false );

if ( ! check_ajax_referer( 'wpse158929_get_terms_for_cpt_submit_', 'nonce', false /*die*/ ) ) {
    $ret['error'] = __( 'Permission error', 'wpfm' );
} else {
    $post_type = isset( $_REQUEST['post_type'] ) ? $_REQUEST['post_type'] : '';
    $taxonomy = isset( $_REQUEST['taxonomy'] ) ? $_REQUEST['taxonomy'] : '';
    $current_selected = isset( $_REQUEST['current_selected'] ) ? $_REQUEST['current_selected'] : '';

    if ( ! $post_type || ! $taxonomy ) {
        $ret['error'] = __( 'Params error', 'wpfm' );
    } else {
        global $wpdb;
        $sql = $wpdb->prepare( 'SELECT t.slug FROM ' . $wpdb->terms . ' t'
            . ' JOIN ' . $wpdb->term_taxonomy . ' AS tt ON tt.term_id = t.term_id'
            . ' JOIN ' . $wpdb->term_relationships . ' AS tr ON tr.term_taxonomy_id = tt.term_taxonomy_id'
            . ' JOIN ' . $wpdb->posts . ' AS p ON p.ID = tr.object_id'
            . ' WHERE tt.taxonomy = %s AND p.post_type = %s AND p.post_status = %s'
            . ' GROUP BY t.slug'
            , $taxonomy, $post_type, 'publish' );
        $include = $wpdb->get_col($sql);
        $ret['html'] = preg_replace( '/<\/?select[^>]*>/', '', my_dropdown_categories( $taxonomy, $current_selected, $include ) );
    }
}

wp_send_json( $ret );
}

对于包含下拉菜单的页面，我有：

                <form action="<?php bloginfo('url'); ?>" method="get">
                <?php
                //$post_type = get_post_type_object( get_post_type($post) ); // GET SINGULAR NAME
                $args = array(
                'public'   => true,
                '_builtin' => false
                );
                $output = 'objects'; // names or objects, note names is the default
                $operator = 'and'; // 'and' or 'or'
                $post_types = get_post_types($args, $output, $operator);
                ksort($post_types);
                echo '<select data-placeholder="I need a:" class="fade-in three selectboxSingle" name="post_type">';
                foreach ( $post_types as $post_type ) {
                $exclude = array('competition');
                if(TRUE === in_array($post_type->name,$exclude)){
                continue;
                }
                // Note: I think you need to use query_var here, rather than slug.
                echo '<option value="'.$post_type->query_var.'">' . ucfirst($post_type->labels->singular_name) . '</option>';
                }
                echo "</select>";
                ?>

                <?php 
                // Set your custom taxonomy
                $taxonomy = "location";
                // Factored out taxonomy dropdown into function my_dropdown_categories() in "functions.php".
                echo my_dropdown_categories( $taxonomy );
                ?>

                <div class="submit-button-blanket">
                    <button class="submit-button alt" type="submit">Search</button>
                </div>
            </form>
        </div>
    </div>
</div>

<script type="text/javascript">
jQuery(document).ready(function($) {
var xhr;
var select_cpt, $select_cpt;
var select_location, $select_location;

$select_cpt = $(".selectboxSingle").selectize({
onChange: function(value) {
    if (!value.length) return;
    select_location.disable();
    select_location.clearOptions();
    select_location.load(function(callback) {
        xhr && xhr.abort();
        xhr = $.ajax({
            url: "<?php echo admin_url('admin-ajax.php'); ?>",
            success: function(results) {
                select_location.enable();
                callback(results);
            },
            error: function() {
                callback();
            }
        })
    });
}
});

$select_location = $('#location').selectize({
valueField: 'name',
labelField: 'name',
searchField: ['name']
});

select_location  = $select_location[0].selectize;
select_cpt = $select_cpt[0].selectize;

select_location.disable();
    });

我现在已经离开了我的深度，任何指导都会非常感激!!