// JavaScript (AJAX)
let xhr = new XMLHttpRequest();
xhr.open('GET', 'process.php?param1=value1', true);
xhr.onload = function() {
    if (xhr.status === 200) {
        console.log(xhr.responseText);
    }
};
xhr.send();

// process.php
<?php
$param = $_GET['param1'];
echo "Received: " . htmlspecialchars($param);
?>

// JavaScript
let xhr = new XMLHttpRequest();
xhr.open('POST', 'process.php', true);
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xhr.onload = function() {
    if (xhr.status === 200) {
        document.getElementById('result').innerHTML = xhr.responseText;
    }
};
xhr.send('name=John&age=30');

// process.php
<?php
$name = $_POST['name'];
$age = $_POST['age'];
echo "Hello, $name. You are $age years old.";
?>

// JavaScript
fetch('api.php', {
    method: 'POST',
    headers: {
        'Content-Type': 'application/json',
    },
    body: JSON.stringify({username: 'john', password: '1234'})
})
.then(response => response.json())
.then(data => console.log(data));

// api.php
<?php
header('Content-Type: application/json');
$data = json_decode(file_get_contents('php://input'), true);
$response = [
    'status' => 'success',
    'user' => $data['username']
];
echo json_encode($response);
?>

// 在PHP文件中添加CORS头
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET, POST');
header('Access-Control-Allow-Headers: Content-Type');

header('Content-Type: text/html; charset=utf-8');
// 或对于JSON
header('Content-Type: application/json; charset=utf-8');

$clean_input = filter_var($_POST['input'], FILTER_SANITIZE_STRING);

$stmt = $pdo->prepare('SELECT * FROM users WHERE email = ?');
$stmt->execute([$_POST['email']]);

session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    if (!isset($_POST['csrf_token']) || $_POST['csrf_token'] !== $_SESSION['csrf_token']) {
        die('Invalid CSRF token');
    }
}

echo htmlspecialchars($user_input, ENT_QUOTES, 'UTF-8');

ob_start('ob_gzhandler');