<form method="post" action="doIscrizione.php">
    <input id="nome" type="text" name="nome" value="Nome" onfocus="this.setAttribute('value','')">
    <br><br>
    <input id="cognome" type="text" name="cognome" value="Cognome" onfocus="this.setAttribute('value','')">
    <br><br>
    <input id="email" type="text" name="email" value="Email" onfocus="this.setAttribute('value','')">
    <br><br>
    <input id="useriscrizione" type="text" name="userid" value="UserId" onfocus="this.setAttribute('value','')">
    <input id="passwiscrizione" type="text" name="password" value="Password" onfocus="this.setAttribute('value','')">
    <br><br>
    <button id="iscriviti" type="button">Iscriviti</button>
</form>

<?php

    error_reporting(E_ALL);
    ini_set( 'display_errors','1');

    session_start();

    $nome = $_REQUEST["nome"];
    $cognome = $_REQUEST["cognome"];
    $email = $_REQUEST["email"];
    $userid = $_REQUEST["userid"];
    $password = $_REQUEST["password"];



    $host = "localhost";
    $username = "root";
    $password = "";
    $db = "iscrizioni";


    $conn = new mysqli($host,$username,$password,$db);

    if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
    };

    $sql ="INSERT INTO `iscrizioni`.`iscrizionitab` (`nome`, `cognome`, `email`,
    `userid`, `password`) VALUES ('$nome', '$cognome', '$email', '$userid',
   '$password')";

    $result = $conn->query($sql);

    $_SESSION["username"] = $userid;
    header('Location: http://localhost/SCHIF_Vizzini_Occhipinti/index.php');
    exit;

?>