<?php 
session_start(); 
$password="pippo";    /* inserire su questa riga la password voluta */
if (isset($_SESSION['login'])) { 
    if (isset($_POST['logout'])) {
        unset($_SESSION['login']);
        $messaggio = "Logout effettuato con successo! Arrivederci!";
    } else {
        header("Location: protetta.php"); 
    } 
} else {
    if (isset($_POST['password'])) {
        if ($_POST['password'] == $password) {
            $_SESSION['login'] = "verificata";
            header("Location: protetta.php");
        } else {
            $messaggio = "Errore: password non corretta!";
        }
    } 
}
?>
<!DOCTYPE html>
<html lang="en" class="wide wow-animation">
  <head>
    <!-- Site Title-->
    <title>Login</title>
    <meta name="format-detection" content="telephone=no">
    <meta name="viewport" content="width=device-width, height=device-height, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
    <meta http-equiv="X-UA-Compatible" content="IE=Edge">
    <meta charset="utf-8">
    <!-- <link rel="icon" href="images/favicon.ico" type="image/x-icon"> -->
    <!-- Stylesheets-->
    <link rel="stylesheet" type="text/css" href="//fonts.googleapis.com/css?family=Roboto:400,300%7CRoboto+Slab:400,700%7CMontserrat:700%7CPacifico">
    <link rel="stylesheet" href="css/style.css">
		<!--[if lt IE 10]>
    <div style="background: #212121; padding: 10px 0; box-shadow: 3px 3px 5px 0 rgba(0,0,0,.3); clear: both; text-align:center; position: relative; z-index:1;"><a href="http://windows.microsoft.com/en-US/internet-explorer/"><img src="images/ie8-panel/warning_bar_0000_us.jpg" border="0" height="42" width="820" alt="You are using an outdated browser. For a faster, safer browsing experience, upgrade for free today."></a></div>
    <script src="js/html5shiv.min.js"></script>
		<![endif]-->
  </head>
  <body>
      <main class="page-content">
        <section class="section section-inset-1">
          <div class="container">
            <h2 align="center">sign in</h2>
            <hr>
            <div class="row">
              <div class="col-xs-12 col-lg-8 col-lg-offset-2">
                <div class="row offset-5">
                  <div class="col-lg-6 col-lg-offset-3">
                    <form name="login" action="login.php" method="post" class="rd-mailform">                 
                      <div class="form-group">
                        <input type="password"  name="password"  class="form-control" value=""/> 
                      </div>
                      <button type="submit" class="btn btn-success btn-sm btn-min-width-lg">sign in</button>
                    </form>
                    <?php 
if(isset($messaggio)) {
    echo $messaggio;
    unset($messaggio);
} 
?> 
                  </div>
                </div>
              </div>
            </div>
          </div>
        </section>
      </main>
</body>
</html>