Well, I need some help. I'm getting around this problem almost 1 day. In this Code that makes the data update for phpmyadmin does not change anything but also gives me no error.
<?php
// definições de host, database, usuário e senha
$conn = mysql_connect("localhost", "root", "");
mysql_select_db("navegador", $conn);
//$id = $_GET['id'];
$ID = $_POST["ID"];
$Nome = $_POST["Nome"];
$NumeroBI = $_POST["NumeroBI"];
$Morada = $_POST["Morada"];
$Telefone = $_POST["Telefone"];
$DataNasc = $_POST["DataNasc"];
$Email = $_POST["Email"];
$Password = $_POST["Password"];
$is_admin = $_POST["is_admin"];
$sqlupdate ="update tb_utilizador SET Nome='$Nome', NumeroBI='$NumeroBI', Morada='$Morada', Telefone='$Telefone', DataNasc='$DataNasc',
Email='$Email', Password='$Password', is_admin='$is_admin' WHERE ID='$ID' " or die (mysql_error());;