模态表单数据未提交

Question

对于我的学校项目，我有以下代码将文件上传到服务器。当上传完成并且文件处理完毕后，页面将重新加载并显示一个模态窗口供用户验证某些数据。问题是，当用户单击提交按钮时，处理表单提交的PHP代码不会被执行。 echo语句打印＆＃34; no＆＃34;警报有效，但if语句中没有任何内容执行。

<div class="wrapper">
    <form class="form-signin text-center" action="#">
        <h2 class="form-signin-heading"><a href="."><img src="img/logo.png" style="width:300px; height:100px;"></a></h2>
        <h4>Resume Upload</h4>
        <br>
        <?php
            if (isset($_SESSION["upload-success"]) && !isset($_POST["update"])){
                if ($_SESSION["upload-success"] = true){
                    echo "
                        <div class='alert alert-info' role='alert' id='verify-banner'><strong>Success!</strong> Resume uploaded successfully.</a></div>
                        <script type='text/javascript'>
                            $(document).ready(function() {
                                $('#edit').modal('show'); 
                            });
                        </script>
                    ";
                }else{
                    echo "<div class='alert alert-danger' role='alert'><strong>Error!</strong> An error occurred while uploading the resume.</div>";
                }
                unset($_SESSION["upload-success"]);
            }
        ?>
        <div class="form-group align-items-center">
            <div class="input-group input-file" name="image">
                <span class="input-group-btn">
                    <button class="btn btn-default btn-choose" type="button">Choose</button>
                </span>
                <input type="text" placeholder='Choose a file...' style="padding-right: 105px;"/>
            </div>
            <br>
            <button class="btn btn-md btn-primary upload" type="submit">Upload</button>
        </div>
        <div id="progressbar" class="progress progress-striped active" style="display:none;">
            <div class="progress-bar" style="width:0%"></div>
        </div>
    </form>
    <div class="modal fade" id="edit">
        <div class="modal-dialog" role="document">
            <div class="modal-content">
                <div class="modal-header">
                    <h5 class="modal-title">Verify Resume Data</h5>
                        <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                            <span aria-hidden="true">&times;</span>
                        </button>
                </div>
                <div class="modal-body">
                    <form name="update" action="<?php echo $_SERVER['PHP_SELF']; ?>">
                        <div class="form-group row">
                            <label class="col-3 col-form-label">First Name</label>
                            <div class="col-9">
                                <input class="form-control" type="text" value="<?php echo $_SESSION['fname']?>" name="fname" id="fname">
                            </div>
                        </div>
                        <div class="form-group row">
                            <label class="col-3 col-form-label">Last Name</label>
                            <div class="col-9">
                                <input class="form-control" type="text" value="<?php echo $_SESSION['lname']?>" name="lname" id="lname">
                            </div>
                        </div>
                        <div class="form-group row">
                            <label class="col-3 col-form-label">Email Address</label>
                            <div class="col-9">
                                <input class="form-control" type="email" value="<?php echo $_SESSION['email']?>" name="email" id="email">
                            </div>
                        </div>
                        <div class="form-group row">
                            <label class="col-3 col-form-label">Phone Number</label>
                            <div class="col-9">
                                <input class="form-control" type="text" step="1" value="<?php echo $_SESSION['phone']?>" name="phone" id="phone">
                            </div>
                        </div>
                        <div class="form-group row">
                            <label class="col-3 col-form-label">Notes</label>
                            <div class="col-9">
                                <textarea class="form-control" type="text" value="" name="notes" id="notes"></textarea>
                            </div>
                        </div>
                        <div class="modal-footer">
                            <button type="button" class="btn btn-secondary" data-dismiss="modal">Cancel</button>
                            <button type="submit" class="btn btn-primary" name="update" id="update"  formmethod="post">Save changes</button>
                        </div>
                    </form>
                </div>
            </div>
        </div>
    </div>
    <?php 
        if (isset($_POST["update"])){
            require_once("db".DIRECTORY_SEPARATOR."db.php");
            $userid = $_SESSION["new-user-id"];
            $note = $_POST["notes"];
            $mydb->query("UPDATE account SET `FirstName`='".$_POST["fname"]."', `LastName`='".$_POST["lname"]."', `EmailAddress`='".$_POST["email"]."', `PhoneNumber`='".$_POST["phone"]."'' WHERE `UserID`='$userid';");
            $mydb->query("INSERT INTO resume_notes(`UserID`, `Note`) VALUES('$userid', '$note') ON DUPLICATE KEY UPDATE `Note`='$note';");
            //echo "<script>alert('yes');</script>";
            unset($_SESSION["fname"]);
            unset($_SESSION["lname"]);
            unset($_SESSION["email"]);
            unset($_SESSION["phone"]);
            unset($_SESSION["new-user-id"]);
            unset($_POST["update"]);
        }else{
            //echo "<script>alert('no');</script>";
        }
    ?>