Greetings to all who have entered
$_GET["id"] = (int)$_GET["id"];
Actually there are htmlspecialchars. For special paranoids like me there is (int). Are there any other commands similar (int) that affect the value of a variable? Suppose any be
$_GET["id"] = (abcdeабвгд)$_GET["id"]; // оставляем только буквы
ps if not, then say so