在下拉列表更改时返回多个ajax响应

Question

我试图让我的ajax根据我选择的下拉列表响应多个值。

这是我的JS更新

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
    <script>
        $('#student_infor').change(function()
        {
            var first = $('#student_infor').val();
            var req = $.get('frm_get_stud_record.php', {dd: first,action: 'ajax'});

            req.done(function(row)
            {
                var whatever = JSON.parse(row);
                $('#studen_title').val(whatever.stu_title);
                $('#student_first_name').val(whatever.stu_first_name);
            });
        });
    </script>

这是我的ajax php

    <?php
$ajax = false;
$dbValue = 1; //or the default value of your choice - matched to the default selection value of the dropdown
if(isset($_GET['action']) && $_GET['action'] == 'ajax' && isset($_GET['dd'])) 
{
    $dbValue = intval( $_GET['dd'] );
    $ajax = true;   
}
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "college_school_system";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT distinct a.stu_unique_id,
                        a.stu_title,
                        a.stu_first_name,
                        a.stu_middle_name,
                        a.stu_last_name,
                        a.stu_gender,
                        a.stu_email_id,
                        a.stu_mobile_no,
                        a.stu_dob,
                        b.stu_course_id,
                        b.stu_batch_id,
                        b.stu_section_id,
                        c.course_name,
                        d.batch_name,
                        e.section_name
                      from stu_info a INNER JOIN stu_academics b
                      ON
                      a.stu_unique_id = b.stu_acad_stu_info_id
                      inner join courses c
                      ON
                      b.stu_course_id = c.course_id
                      INNER JOIN batches d
                      ON
                      b.stu_batch_id = d.batch_id
                      INNER JOIN section e
                      ON
                      b.stu_section_id = e.section_id 
                      where a.stu_unique_id = $dbValue
                      ORDER BY d.batch_name DESC";//die($sql);
$res = mysqli_query($conn,$sql);
$title = '';
$f_name = '';
while ($row = mysqli_fetch_array($res)){



    $f_name = $row['stu_first_name'];
    $m_name = $row['stu_middle_name'];
    $l_name = $row['stu_last_name'];
    $title  = $row['stu_title'];
    $gender = $row['stu_gender'];
    $email  = $row['stu_email_id'];
    $mobile = $row['stu_mobile_no'];
    $birth  = $row['stu_dob'];
    //$title     =  "$title";
    if($ajax) echo $title;
    if($ajax) echo $f_name;
    }
  //die($dataTable);  

?>

我在这里尝试实现的是让Ajax返回多个值，这样我就可以在各自的输入类型文本框中插入这些返回的值。