成功的Ajax jQuery如何获取PHP传递的结果值

How I can get the success (data) value on Ajax? I want to get the value of firstname and lastname, which are Kevin Yam.

Example I want to set input value, document.getElementById("reply").value = "Kevin Yam"

Ajax code:

$.ajax({
    type:'post',
    url:'getuser_reply_name.php',
    data:{get_reply_postid:post_id,get_reply_commentid:comment_id},
    cache:false,
    success: function (data){
        console.log(data);
    }
});

getuser_reply_name.php code:

if($stmt = $conn->prepare($query)) {

    $stmt->execute();

    $stmt->bind_result($user_firstname, $user_lastname);

        while ($stmt->fetch()) {

            $userdetails = array(
                'u_firstname' => $user_firstname,
                'u_lastname' => $user_lastname
            );

            header('Content-Type: application/json');
            echo json_encode($userdetails);
        }
    $stmt->close();
}

Console log result:

1.Add dataType:"JSON", in your $.ajax, so that it automatically parse json data coming from php.

2.Inside success fetch data from response using keys(what you are seeing in console.log())

Do like below:-

$.ajax({
    type:'post',
    url:'getuser_reply_name.php',
    data:{get_reply_postid:post_id,get_reply_commentid:comment_id},
    dataType:'json', //add dataType
    cache:false,
    success: function (data){
        $("#reply").val(data.u_firstname+' '+data.u_lastname); // put value to input box
    }

});

$.ajax({
    type:'post',
    url:'getuser_reply_name.php',
    data:{get_reply_postid:post_id,get_reply_commentid:comment_id},
    cache:false,
    dataType: 'json', // what type of data do we expect back from the server
      encode: true,
    success: function (data){
        console.log(data);
    }
});

you will get object of array in response