而不是\'cat\' => 12 和$wp_query 使用\'category_name\' => slug 和get_posts().

以下是其工作原理的基本示例：

PHP

add_action( \'wp_loaded\', array ( \'T5_Ajax_Search\', \'init\' ) );

/**
 * Ajaxify the search form.
 */
class T5_Ajax_Search
{
    /**
     * The main instance. You can create further instances for unit tests.
     * @type object
     */
    protected static $instance = NULL;

    /**
     * Action name used by AJAX callback handlers
     * @type string
     */
    protected $action = \'t5_ajax_search\';

    /**
     * Handler for initial load.
     *
     * @wp-hook wp_loaded
     * @return void
     */
    public static function init()
    {
        NULL === self::$instance and self::$instance = new self;
        return self::$instance;
    }

    /**
     * Constructor. Registers the actions.
     *
     *  @wp-hook wp_loaded
     *  @return object
     */
    public function __construct()
    {
        $callback = array ( $this, \'search\' );
        add_action( \'wp_ajax_\'        . $this->action,        $callback );
        add_action( \'wp_ajax_nopriv_\' . $this->action, $callback );
        add_action( \'wp_enqueue_scripts\', array ( $this, \'register_script\' ) );
    }

    /**
     * Callback for AJAX search.
     *
     * @wp-hook wp_ajax_t5_ajax_search
     * @wp-hook wp_ajax_nopriv_t5_ajax_search
     * @return void
     */
    public function search()
    {
        $args  = array ( \'s\' => $_POST[\'search_term\'] );
        $args  = apply_filters( \'t5_ajax_search_args\', $args );
        $posts = get_posts( $args );
        if ( $posts )
        {
            $this->render_search_results( $posts );
        }
        else
        {
            print \'<b>nothing found</b>\';
        }
        exit;
    }

    /**
     * Create markup from $posts
     *
     * @param array $posts Array of post objects
     * @return void
     */
    protected function render_search_results( $posts )
    {
        print \'<ul class="t5-ajax-search-results">\';

        foreach ( $posts as $post )
        {
            printf(
                \'<li><a href="%1$s">%2$s</a></li>\',
                get_permalink( $post->ID ),
                esc_html( $post->post_title )
            );
        }
        print \'</ul>\';
    }

    /**
     * Register script and local variables.
     *
     * @wp-hook wp_enqueue_scripts
     * @return void
     */
    public function register_script()
    {
        wp_enqueue_script(
            \'t5-ajax\',
            #plugins_url( __FILE__ ) . \'/search.js\',
            plugins_url( \'search.js\', __FILE__ ),
            array ( \'jquery\' ),
            NULL,
            TRUE
        );

        wp_localize_script(
            \'t5-ajax\',
            \'T5Ajax\',
            array(
                \'ajaxurl\' => admin_url( \'admin-ajax.php\' ),
                \'action\'  => $this->action
            )
        );
    }
}

JavaScriptsearch.js

jQuery( function( $ ) {
    // search filed
    var $s = $( \'#s\' );
    // the search form
    var $sForm = $s.closest( \'form\' );
    console.log( $sForm );
    $sForm.on( \'submit\', function( event) {
        event.preventDefault();
        $.post(
            T5Ajax.ajaxurl,
            {
                action:     T5Ajax.action,
                search_term: $s.val()
            },
            function( response ) {
                // just append the result to the search form.
                $sForm.append( response );
            }
        );
    });
});

限制搜索

add_filter( \'t5_ajax_search_args\', \'restrict_t5_search\' );

function restrict_t5_search( $args )
{
    $args[\'post_type\'] = array ( \'post\', \'fod_videos\' );
    $args[\'category_name\']       = \'category-slug\';
    return $args;
}