<?php
print_r ($_POST);
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<form action="/" method="post">
<input type="text" name="name" placeholder="ваше имя">
<textarea name="comment"></textarea>
<input type="hidden" name="id_user" value="1313">
<input type="submit" value="отправить">
</form>
</body>
http://localhost/
Простой
Простой
Средний