<?php
$redirect_array = array(
1 => "http://www.example.com/page1.html",
2 => "http://www.example.com/specialpage.html",
3 => "http://www.example.com/order.html",
);
$header = "http://www.example.com/";
if (isset($_GET['page']) && !empty($redirect_array[$_GET['page']])) {
    $header = $redirect_array[$_GET['page']];
}
header("Location: ".$header);
exit;
?>