Javascript 如何向模式PHP、MySQL和Ajax添加数据

我写了这段代码：

<div class="container">
<div class="row">
    <div class="col-md-3">
        <div id="accordion" role="tablist" aria-multiselectable="true">
            <div class="card">
                <div class="card-header" role="tab" id="headingOne">
                    <h5 class="mb-0">
                        Message options
                    </h5>
                </div>

                <div id="collapseOne" class="collapse show" role="tabpanel" aria-labelledby="headingOne">
                    <div class="card-block">
                        <table class="table">
                            <tr>
                                <td>
                                    <a href="?messages=inbox"><i class="fa fa-inbox"></i> Inbox</a>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    <a href="?messages=read"><i class="fa fa-envelope"></i> Read</a>
                                </td>
                            </tr>
                            <tr>
                                <td>
                                    <a href="?messages=trash"><i class="fa fa-trash"></i> Trash</a>
                                </td>
                            </tr>
                        </table>
                    </div>
                </div>
            </div>
        </div>
    </div>
    <div class="col-md-9">
        <div class="card">
            <div class="card-header">
                Messages
            </div>
            <div class="card-block">
                <table class="table mx-auto" id="table">
                    <thead>
                    <tr>
                        <th>Number</th>
                        <th>Subject</th>
                        <th>Time added</th>
                        <th>More</th>
                    </tr>
                    </thead>
            </div>
            <?php

            if((isset($_GET['messages']) && $_GET['messages'] == 'inbox') || !isset($_GET['messages'])) {
                $id = $_SESSION['id'];
                $messages = $database->getDataAsArray("SELECT * FROM messages WHERE userId = $id AND messageDeleted = 0");
            }
            elseif(isset($_GET['messages']) && $_GET['messages'] == 'read' ){
                $id = $_SESSION['id'];
                $messages = $database->getDataAsArray("SELECT * FROM messages WHERE userId = $id AND messageRead = 1");
            }
            elseif (isset($_GET['messages']) && $_GET['messages'] == 'trash'){
                $id = $_SESSION['id'];
                $messages = $database->getDataAsArray("SELECT * FROM messages WHERE userId = $id AND messageDeleted = 1");
            }
            if(!$messages){
                echo '<tr>

                              <td colspan="3" style="text-align: center">No new messages in the inbox</td>

                          </tr>';
            }
            elseif(!isset($_GET['messages']) || $_GET['messages'] == 'inbox'){
                foreach ($messages as $message){
                    $number = $message['id'];
                    $subject = $message['subject'];
                    $time_added = $message['time_added'];
                    if($message['messageRead'] == 0){
                        echo "<tr class='table-active'><td>$number</td><td>$subject</td><td>$time_added</td></tr>";
                    }
                    else{
                        echo "<tr><td>$number</td><td>$subject</td><td>$time_added</td><td><div class='dropdown'>
                                  <button class='btn btn-secondary btn-sm ' type='button' id='dropdownMenu2' data-toggle='dropdown' aria-haspopup='true' aria-expanded='false'>
                                        <i class='fa fa-ellipsis-v'></i>
                                  </button>
                                  <div class='dropdown-menu dropdown-menu-left' aria-labelledby='dropdownMenu2'>
                                    <a class='dropdown-item' href='#'>Preview</a> 
                                    <a class='dropdown-item' href='#'>Mark as read</a>
                                    <a class='dropdown-item' href='#'>Mark as unread</a>
                                  </div>
                              </div>
                          </td></tr>";
                    }
                }
            }
            else{
                foreach ($messages as $message){
                    $number = $message['id'];
                    $subject = $message['subject']; // needs to become subject new row in database
                    $time_added = $message['time_added'];
                    echo "<tr><td>$number</td><td>$subject</td><td>$time_added</td>

                          <td><div class='dropdown'>
                                  <button class='btn btn-secondary btn-sm ' type='button' id='dropdownMenu2' data-toggle='dropdown' aria-haspopup='true' aria-expanded='false'>
                                        <i class='fa fa-ellipsis-v'></i>
                                  </button>
                                  <div class='dropdown-menu dropdown-menu-left' aria-labelledby='dropdownMenu2'>

                                    <button class='dropdown-item' data-toggle='modal' data-number='$number' data-target='#exampleModalLong'>Preview</button> 
                                    <a class='dropdown-item' href='#'>Mark as read</a>
                                    <a class='dropdown-item' href='#'>Mark as unread</a>
                                  </div>
                              </div>
                          </td></tr>";
                }
            }
            ?>
        </div>
    </div>
</div>

<!-- Modal -->
<div class="modal fade" id="exampleModalLong" tabindex="-1" role="dialog" aria-labelledby="exampleModalLongTitle" aria-hidden="true">
    <div class="modal-dialog" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title" id="exampleModalLongTitle">Modal title</h5>
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                    <span aria-hidden="true">&times;</span>
                </button>
            </div>
            <div class="modal-body">
                ...
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
                <button type="button" class="btn btn-primary">Save changes</button>
            </div>
        </div>
    </div>
</div>
<script>
    $('#exampleModalLong').on('show.bs.modal', function(e) {
        var number = $(e.relatedTarget).data('number');
        $.ajax({
            type: 'POST',
            url: 'retrieveData.php',
            data: {
                'id': number
            },
            success: function(data){
                console.log(data);
            },
            error: function(error){
                alert(error);
            }
        });
    });
</script>

getDataAsArray函数完全不安全我知道我需要使用准备好的语句：

public function getDataAsArray($myQuery){
    $this->connection = mysqli_connect($this->host, $this->dbUsername, $this->dbPassword, 'portal');
    $query = mysqli_query($this->connection, $myQuery);
    $results = array();
    while($line = mysqli_fetch_array($query)){
        $results[] = $line;
    }
    return $results;
}

谁能帮我修复我的Ajax函数吗？我想错误就在那里，这样我就可以在model中显示消息的数据了

echo$数据；其中$data是一个数组，将只输出文本数组，如下所述：

数组始终转换为字符串数组；因此,， echo和print本身不能显示数组的内容

用于将数组格式化为JSON JavaScript对象表示法：

echo json_encode($data);

---

顺便说一下，您可以去掉返回的$data；假设给定的代码不在函数中，并且该文件不包含在包含或要求的代码中的任何其他位置，则它不会执行任何操作。

使用浏览器的调试工具。开发控制台中是否有错误？是否执行了JavaScript代码？是否进行了AJAX调用？它是否包含您期望的数据？服务器的响应是什么？@David控制台中没有错误，没有服务器响应。Ajax被调用，Javascript也被调用。在PHP中打开错误报告。检查PHP错误日志。如果没有响应，您的意思是响应完全为空，那么这可能是PHP白色死亡屏幕，这意味着服务器端发生了错误。如果“无响应”是指请求无限期挂起，那么听起来您的服务器端代码中可能存在逻辑错误，可能导致无限循环，您需要进行一些调试才能找到它。@David PHP错误日志已打开。日志中没有任何错误。这很奇怪

echo json_encode($data);