coba.php

if($user == $dbuser && $pass == $dbpass){
    echo "<h1>Login Berhasil</h1>";
    $_SESSION['start'] = time();
    $_SESSION['expired'] = $_SESSION['start'] + (30 * 60);
    header("location:index.php");
}else{
    if(isset($_SESSION["salah"])){
        $_SESSION["salah"]++;

    }else{
        $_SESSION["salah"] = 1;
    }
    header("location:index.php");