我正在使用WordPress的代码片段插件发送jQuery Ajax请求，但我一直收到

发布https://example.com/wp-admin/admin-ajax.php 400（错误请求）

我已经尝试了似乎有一千种方法来制定Ajax请求，下面是stackoverflow、jQuery论坛、WordPress论坛中的示例，并且还在继续。总是有相同的错误。

以下是我当前在代码段编辑器中拥有的内容：

JavaScript code

var jq = jQuery.noConflict();
// a bunch of code to determine what day is selected on a calendar, this all works up until the ajax call
jq(".c-day-content").click(function () {
    console.log ("handled the day being picked quite nicely...");
        day = jq(this).text();
        day = day.replace(/[^0-9]/g,\'\');
        console.log("day=" + day);
    bookingStart = bookingStart.concat(day);
    //query the db looking for time slots with appointments and returning this array

    var ajaxurl = \'<?php echo admin_url( \'admin-ajax.php\' ) ?>\';
    console.log(ajaxurl);

    jq.ajax({
        url: ajaxurl,
        data: {
            action: "retrieveAttendees",
            dateSelected: bookingStart //bookingStart is variable that has a string value
        },
        method: \'POST\',
        success: function(data, XMLHttpRequest) {
            //never been able to make it to here
            console.log(JSON.stringify(data));
        },
        error: function (XMLHttpRequest, textStatus, errorThrown) {
            console.log("we failed again: " + JSON.stringify(XMLHttpRequest));
            console.log("text status: " + textStatus);
            console.log("errorThrown: " + errorThrown)
        }
    }); 

然后我的php 同一代码段编辑器中的处理程序：

function retrieveAttendees_request() {
console.log("made it to the ajax request"); // I\'ve never made it here either
if ( isset($_REQUEST)) {
    $bookingDay = $_REQUEST[\'dateSelected\'];
    global $wpdb;
    $sql = $wpdb->prepare("select apps.bookingStart, COUNT(*) as booked from wp_amelia_customer_bookings as books inner join wp_amelia_appointments as apps on books.appointmentId = apps.id where apps.bookingStart like %s\'%\' and apps.status = \'approved\' GROUP BY books.appointmentId;", $bookingDay);
    $result = $wpdb->get_row($sql, ARRAY_A);
    echo json_encode($result);
}
  die();
}
add_action(\'wp_ajax_retrieveAttendees\', \'retrieveAttendees_request\');
add_action(\'wp_ajax_nopriv_retrieveAttendees\', \'retrieveAttendees_request\');

我尝试将数据类型添加到Ajax中，但没有成功。尝试同时添加数据类型和内容类型，但没有成功。我不知道为什么我总是收到同样的POST 400错误请求错误。如果有任何帮助和见解，我将不胜感激。