下面使用的是jQuery UI自动完成，它自3.3版起就包含在WordPress中。（我借用了@Rarst :D） 。

这仍然不是你想要的，但给了你一个很好的起点。下面使用了基本的jQuery UI样式，但您可以use the one that\'s currently worked out on trac 并从插件文件夹中调用它。

class AutoComplete {

    static $action = \'my_autocomplete\';//Name of the action - should be unique to your plugin.

    static function load() {
        add_action( \'init\', array( __CLASS__, \'init\'));
    }

    static function init() {
        //Register style - you can create your own jQuery UI theme and store it in the plug-in folder
        wp_register_style(\'my-jquery-ui\',\'http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css\');    
        add_action( \'get_search_form\', array( __CLASS__, \'get_search_form\' ) );
        add_action( \'wp_print_footer_scripts\', array( __CLASS__, \'print_footer_scripts\' ), 11 );
        add_action( \'wp_ajax_\'.self::$action, array( __CLASS__, \'autocomplete_suggestions\' ) );
        add_action( \'wp_ajax_nopriv_\'.self::$action, array( __CLASS__, \'autocomplete_suggestions\' ) );
    }

    static function get_search_form( $form ) {
        wp_enqueue_script( \'jquery-ui-autocomplete\' );
        wp_enqueue_style(\'my-jquery-ui\');
        return $form;
    }

    static function print_footer_scripts() {
        ?>
    <script type="text/javascript">
    jQuery(document).ready(function ($){
        var ajaxurl = \'<?php echo admin_url( \'admin-ajax.php\' ); ?>\';
        var ajaxaction = \'<?php echo self::$action ?>\';
        $("#secondary #searchform #s").autocomplete({
            delay: 0,
            minLength: 0,
            source: function(req, response){  
                $.getJSON(ajaxurl+\'?callback=?&action=\'+ajaxaction, req, response);  
            },
            select: function(event, ui) {
                window.location.href=ui.item.link;
            },
        });
    });
    </script><?php
    }

    static function autocomplete_suggestions() {
        $posts = get_posts( array(
            \'s\' => trim( esc_attr( strip_tags( $_REQUEST[\'term\'] ) ) ),
        ) );
        $suggestions=array();

        global $post;
        foreach ($posts as $post): 
                    setup_postdata($post);
            $suggestion = array();
            $suggestion[\'label\'] = esc_html($post->post_title);
            $suggestion[\'link\'] = get_permalink();

            $suggestions[]= $suggestion;
        endforeach;

        $response = $_GET["callback"] . "(" . json_encode($suggestions) . ")";  
        echo $response;  
        exit;
    }
}
AutoComplete::load();