<?php
// 设置HTTP状态码为400（错误请求）
http_response_code(400);
exit;
?>

<?php
header('Content-Type: text/plain');
echo "Error: Invalid request parameters";
exit;
?>

<?php
header('Content-Type: application/json');
echo json_encode("Error: Authentication failed");
exit;
?>

<?php
header('HTTP/1.1 500 Internal Server Error');
echo "Database connection failed";
exit;
?>

$.ajax({
    url: 'your_php_script.php',
    type: 'POST',
    success: function(response) {
        // 处理成功响应
    },
    error: function(xhr, status, error) {
        // 处理错误
        console.log('Error:', xhr.status, error);
        console.log('Response:', xhr.responseText);
    }
});