<?php
$servername = "localhost";
$username = "username";
$passwd = "password";
$dbname = "myDB";

// Create connection
$conn = new mysqli($servername, $username, $passwd, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$username = $_POST['user'];
$password = $_POST['pass'];

$query = mysql_query(INSERT INTO admin (username, password) VALUES('oji', 'admin123');
$data = mysql_fetch_array($query);

if ($data['jumlah'] >= 1){
    session_start();
    $_SESSION['username']    = $username;
    $_SESSION['password']    = $password;

    echo "<script>alert('Selamat datang $username'); window.location = 'admin/tambah.php'</script>";
} else {
    echo "<script>alert('Username dan Password tidak valid.'); window.location = 'index.html'</script>";
}
?>