Cannot pass data to PhpMyAdmin by ajax

Index.php

This is part of my Index.php code, I cannot pass data to the file “action/viewupdate.php” using ajax.

                                    <tr>
                                        <td><?php echo $row['word'] ?></td>
                                        <td><?php echo $row['comment'] ?></td>
                                        <td><?php echo $row['viewno'] ?>
                                            <Span id="view_update<?php echo $count; ?>" style="display:none;font-weight:1000;color:green;font-size:12px"></Span>
                                        </td>
                                        <form action="" method="post" id="viewupdate<?php echo $count; ?>">
                                            <td><input type='button' name='viewupdate' value='Update' data-action="viewupdate<?php echo $count; ?>" class="button" /></td>
                                            <input type="hidden" id="userselectchannel<?php echo $count; ?>" name="userselectchannel<?php echo $count; ?>" value="<?php echo $row['videoline'] ?>">
                                            <input type="hidden" id="updateno<?php echo $count; ?>" name="updateno<?php echo $count; ?>" value="">
                                            <td style="display:none" id="saveupdateclm<?php echo $count; ?>"><input id="saveupdatebtn<?php echo $count; ?>" type='button' name='saveupdate<?php echo $count; ?>' value='Save**strong text**' data-action="saveupdate<?php echo $count; ?>" class="confirmbutton" /></td>
                                        </form>
                                    </tr>
                                    <script>
                                        $('#saveupdatebtn<?php echo $count; ?>').click(function() {
                                            var updateno1 = $('#updateno<?php echo $count; ?>').val();
                                            var userselectchannel1 = $('#userselectchannel<?php echo $count; ?>').val();
                                            var username1 = "<?php echo $_SESSION['nick_name']; ?>";
                                            /* alert(updateno + "n" + userselectchannel + "n" + username); */
                                            $.ajax({
                                                url: 'action/viewupdate.php',
                                                type: 'POST',
                                                data: {
                                                    "updateno": updateno1,
                                                    "userselectchannel": userselectchannel1,
                                                    "username": username1
                                                },
                                                cache: false,
                                                success: function(msg) {
                                                    console.log(data);
                                                    var x = document.getElementById("errorpopup2");
                                                    x.innerHTML = "<div style='color:#21ff21;'>Video <?php echo $count ?>Views update successfully</div>";
                                                    x.className = "show";
                                                    setTimeout(function() {
                                                        x.className = x.className.replace("show", "");
                                                    }, 3000);

                                                    $("#saveupdatebtn<?php echo $count; ?>").attr("disabled", "disabled");
                                                    $('#saveupdatebtn<?php echo $count; ?>').css('cursor', 'not-allowed');
                                                    return false;
                                                },
                                                error: function(msg) {
                                                    var x = document.getElementById("errorpopup2");
                                                    x.innerHTML = "Unknown Error Occured";
                                                    x.className = "show";
                                                    setTimeout(function() {
                                                        x.className = x.className.replace("show", "");
                                                    }, 3000);
                                                    return false;
                                                }

                                            });
                                        });

Viewupdate.php

<?php 
include_once "../../system/connect.php";
$updateno=$_POST['updateno'];
$userselectchannel=$_POST['userselectchannel'];
$username=$_POST['username'];
$time = date('Y-m-d H:i:s');
$updatetitle = $updateno;
$sql = "INSERT INTO `pagecontent_update`(`update-user`, `update-time`, `update-info`) 
VALUES ('$username','$time','$updatetitle')";
if (mysqli_query($link, $sql)) {
    echo json_encode(array("statusCode"=>200));
} 
else {
    echo json_encode(array("statusCode"=>201));
}
?>

PhpMyAdmin Screenshot
https://drive.google.com/file/d/1NcTYZNWhFMSQZMCZiNrTcfX-MPN4UGnT/view?usp=sharing

As the picture shown, data cannot pass to Viewupdate.php using ajax. As I wish that when user press the submit button, the data will stored into the database without refresh. Thx a lot.
If you need more information, please contact me at any time.