index.php

<?php
    session_start();

    if(isset($_POST['submit'])) {
        $dbCon = mysqli_connect("localhost", "root", "-------", "Login");

        $username = $_POST['name'];
        $password = $_POST['password'];

        $sql = "SELECT id, username, password FROM users WHERE username = '$username' AND active = '1'";

        $query = mysqli_query($dbCon, $sql);
        if($query) {
            $row = mysqli_fetch_row($query);
            $userId = $row[0];
            $dbUsername = $row[1];
            $dbPassword = $row[2];
        }

        if($username == $dbUsername && $password == $dbPassword) {
                $_SESSION['username'] = $username;
                $_SESSION['id'] = $userId;
                header('Location: page.php');
            } else {
                $error = "Incorrect Username/Password!";
        }
    }
?>

<!DOCTYPE html>
<html>
<head>

    <!-- Title -->
    <title> Login </title>

    <!-- Google Font -->
    <link href="https://fonts.googleapis.com/css?family=PT+Sans+Caption" rel="stylesheet">

    <!-- CSS -->
    <link rel="stylesheet" href="css/main.css">

</head>
<body>

    <form method="POST" action="index.php">
        <div id="loginContainer">
            <h2>LOGIN</h2>
            <input type="text" placeholder="USERNAME" name="name" />
            <input type="password" placeholder="PASSWORD" name="password" />

            <div id="error"><?php echo $error; ?></div>

            <input type="submit" name="submit" value="LOGIN" />
        </div>
    </form>

    <h3>username = username<br />password = password</h3>

</body>
</html>