使用 AJAX 和 PHP 显示数据

Question

我尝试编写此代码并遇到麻烦说 警告：第 15 行 E:\xampp\htdocs mpi\get_chat_interface.php 中未定义的数组键“user_name”

这是我的 php 代码`

try {
    $pdo = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    $recipientUsername = $_POST['user_name'];

    $stmt = $pdo->prepare("SELECT message FROM messages WHERE sender = ? OR receiver = ?");
    $stmt->execute([$recipientUsername, $recipientUsername]);

    echo "<div class='live-chat-name'><p>$recipientUsername</p></div>";
    echo "<div class='chat-content'>";

    while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) {
        $message = $row['message'];
        echo "<p>$message</p>";
    }

    echo "</div>";
    echo "<div class='chat-input'>";
    echo "<form id='chatForm'>";
    echo "<input type='text' id='messageInput' placeholder='Send Message...' required>";
    echo "<input type='hidden' id='recipientUsername' value='$recipientUsername'>";
    echo "<button type='submit'>Send</button>";
    echo "</form>";
    echo "</div>";
} catch (PDOException $e) {
    echo "Error: " . $e->getMessage();
}

这是 JS

function loadChatInterface(user_name) {
    // AJAX request to load the chat interface for a specific user
    $.ajax({
        url: 'get_chat_interface.php',
        method: 'POST',
        data: { user_name: user_name }, // Use the correct key here
        success: function (data) {
            $('#chatInterface').html(data);
        }
    });
}

Answer 1

你忘了添加数据的contentType

contentType: "application/x-www-form-urlencoded;

，你的请求应该是这样的：

function loadChatInterface(user_name) {
    // AJAX request to load the chat interface for a specific user
    $.ajax({
        url: 'get_chat_interface.php',
        method: 'POST',
        data: { user_name: user_name }, // Use the correct key here
        contentType: "application/x-www-form-urlencoded; charset=UTF-8",
        success: function (data) {
            $('#chatInterface').html(data);
        }
    });
}