这是一个jQuery脚本，我正在使用它将输入发布到数据库，假设提交数据的用户已登录，并且没有为用户提交数据的项目创建现有条目。

目前它没有产生任何结果，我也不完全清楚为什么，因为我不经常使用jQuery。

下面是一个流程图，说明了我正在努力实现的目标：

function csv_three_script() {
    //Include Javascript library
    wp_enqueue_script(
        \'csv3\', 
        plugins_url( 
            \'/js/demo.js\', 
            __FILE__ 
        ), 
        array( 
            \'jquery\'
        )
     );
     wp_localize_script(
     \'csv3\',
     \'MyAjax\', array(
     \'ajaxurl\' => admin_url( \'admin-ajax.php\')));
}
add_action( \'wp_enqueue_scripts\', \'csv_three_script\' );



function check_db(){
global $table;
global $quanid;
$hf_userid = get_current_user_id();
global $wpdb;
$wpdb->get_results( $wpdb->prepare("SELECT count( 1 ) FROM $table WHERE ItemID = \'$quanid\' AND user = \'$hf_userid\'", ARRAY_A));
}
add_action(\'wp_ajax_check_db\', \'check_db\');

function update_entry(){
global $quanid;
$price = isset($_POST[$quanid]);
$hf_userid = get_current_user_id();
global $table;
global $wpdb;
    $wpdb->update( $wpdb->prepare( \'$table\',
    array(
        \'ItemID\' => \'$quanid\',
        \'Price\' => $price,
        \'user\' => $hf_userid)));

}
add_action(\'wp_ajax_update_entry\', \'update_entry\');


function post_entry(){
global $quanid;
$price = isset($_POST[$quanid]);
$hf_userid = get_current_user_id();
global $wpdb;
$wpdb->insert( $wpdb->prepare( 
    \'$table\', 
    array( 
        \'ItemID\' => \'$quanid\',
        \'Price\'  => $price,
        \'user\'   => $hf_userid
    ), 
    array( 
        \'%d\', \'%d\', \'%d\'
    ) 
));
die();
return true;
}
add_action(\'wp_ajax_post_entry\', \'post_entry\');

jQuery(document).ready(function() {
    var data = {
        action: \'is_user_logged_in\'
    };
    jQuery.post(ajaxurl, data, function(response) {
            if (response == \'yes\') {
                // user is logged in
                jQuery.ajax({
                        type: \'POST\',
                        url: MyAjax.ajaxurl,
                        data: {
                            "action": "check_db",
                            "user": user,
                            "ItemID": ItemID
                        },
                        function(data) {
                            if (data.exists) {
                                //existing entry found, update entry
                                function UpdateRecord(id) {
                                    jQuery.ajax({
                                        type: \'POST\',
                                        url: MyAjax
                                            .ajaxurl,
                                        data: {
                                            "action": "update_entry",
                                            "ItemID": ItemID,
                                            "Price": Price,
                                            "user": user
                                        },
                                        success: function(
                                            response
                                        ) {
                                            alert
                                                (
                                                    "Price successfully submitted."
                                                );
                                        }
                                    });
                                }
                            } else {
                                //existing entry not found, create new entry
                                jQuery("#submit").click(
                                    function() {
                                        var name = jQuery(
                                            "#ItemID").val();
                                        jQuery.ajax({
                                            type: \'POST\',
                                            url: MyAjax
                                                .ajaxurl,
                                            data: {
                                                "action": "post_entry",
                                                "ItemID": ItemID,
                                                "Price": Price,
                                                "user": user
                                            },
                                            success: function(
                                                response
                                            ) {
                                                alert
                                                    (
                                                        "Price successfully submitted."
                                                    );
                                            }
                                        });
                                    });
                            });
                    }
                }, \'JSON\');
        } else {
            // user is not logged in
            alert("You must be logged in to submit prices.");
        }
    }
});