Javascript와 PHP 간에 데이터를 원활하게 전송하는 방법은 무엇입니까?

<code class="js">// Data to be sent to PHP script
const data = {tohex: 4919, sum: [1, 3, 5]};

// Create an XMLHttpRequest object
const httpc = new XMLHttpRequest();

// Open a POST request to the PHP script
httpc.open("POST", "server.php", true);

// Set the request header to specify the content type
httpc.setRequestHeader("Content-Type", "application/json");

// Send the data to the PHP script
httpc.send(JSON.stringify(data));

// Process the response from the PHP script
httpc.onreadystatechange = function() {
  if (httpc.readyState === 4 && httpc.status === 200) {
    console.log(httpc.responseText);
  }
};</code>

<code class="php">// Retrieve data from the HTTP request body
$data = json_decode(file_get_contents("php://input"));

// Calculate the hex value and sum
$tohex = base_convert($data->tohex, 10, 16);
$sum = array_sum($data->sum);

// Echo the results
echo json_encode([$tohex, $sum]);</code>