Nice simple solution for those that require something simple. Only thing I would consider adding is some security on the 'protected page/s'
That's simple enough by passing the form field 'view' as a SESSION variable.
Not informing you how to do it because you know but for others:
Open the session by inserting the line below at the very top of the page:
<?php session_start() ?>
Amend this line:
<?php if (in_array($_POST['view'], $passwords)){ ?>
To:
<?php $_SESSION['view'] = $_POST['view']; ?>
<?php if (in_array($_SESSION['view'], $passwords)){ ?>
Then on ALL protected pages add at the very top the code below: (the protected pages need to have a .php extension....so in the example Rob provided 'page.html' becomes 'page.php' or whatever you want to name it.)
<?php session_start() ?>
<?php
if (!isset($_SESSION['view'])) {
header("Location: access.php");
}
?>