我正在尝试更新投票插件的post meta。特别是它调用update_post_meta() 根据ajax请求。代码如下：

function add_settings_menu() {
     add_options_page(\'Contested Settings\', \'Contested Settings\', 1, \'manage_options\', \'contested_settings\');
}

function contested_settings() {
    include("contested_admin_settings.php");
}

function get_posts_votes($post) {
    $votes = get_post_meta($post, \'votes\', true );
    return $votes;
}

function add_contested_voting($category, $post) {
    if (in_category($category, $post)) {
            wp_enqueue_script(\'jquery\');
            $post = get_post($post);
            $post_id = (int)$post->ID;
            add_post_meta($post_id, \'votes\', \'0\', true);
            /*if($votes == \'\') { 
                update_post_meta($post, \'votes\', \'0\'); 
                $votes = get_post_meta( $post, \'votes\', true ); 
            }*/
        ?>
            <form id=\'voting-form\'>
                <strong>Vote now!</strong><br />
                <label id=\'votes\'><?php echo get_posts_votes($post); ?></label>
                <input type=\'button\' id=\'vote_up\' value=\'+1\' />
            </form>
            <script>
                $(function() {
                    ajaxurl = "<?php echo admin_url(\'admin-ajax.php\'); ?>";
                    $("#vote_up").click(function() {
                        var data = {
                            action: \'contested\',
                            votes: \'<?php echo $votes; ?>\',
                            post: \'<?php echo $post_id; ?>\'
                        };
                        $.post(ajaxurl, data, function(data) { 
                            $("#voting-form").html(data);
                        });
                    });
                });
            </script>
        <?
    }
}

function ajax_posted() {
    $votes_plus = $_POST[\'votes\']+1;
    $id = $_POST[\'post\'];
    if (update_post_meta($id, \'votes\', $votes_plus)) {
        $votes_ret = get_post_meta($id, \'votes\', true);
        echo "Thanks for voting! ".$votes_ret." vote.";
    } else {
        echo "Voting failed!";
    }
    die();
}

add_action(\'admin_menu\', \'add_settings_menu\');
add_action(\'wp_ajax_contested\', \'ajax_posted\');