Why are POST parameters not being passed?

Question

PHP

I pass POST parameters, but PHP does not see them, it displays only a test string. Tried with GET, everything worked as it should.
JS

fetch('test.php', {
    method: 'POST',
    headers: {'Content-Type': 'application/json'},
    body: JSON.stringify({ code }) // { code:string }
})

PHP

<?
echo 'Test'; // Тестовая строка, выводится
echo $_POST['code']; // Не выводится

Here with GET:
JS

fetch( 'test.php?' + new URLSearchParams({ code }) );

PHP

<?
echo $_GET['code']; // Работает

Answer 1

Because the variable $_POSTcan only work with application/www-x-form-urlencoded and multipart/form-data . The custom type Body as JSON already needs to be obtained and parsed by handles.

<?php
$json = json_decode(file_get_contents('php://input'), true);
var_dump($json);

If you still want through $_POST, you need to pass the request body through FormData , instead of JSON.