automatic page nav change

<?php
// Page name
$page_name = ltrim($_SERVER["PHP_SELF"],'/');
$page_name = rtrim($page_name,'.php');
 
// Default footer text
$footer = '© 2010 Melted, LLC';
 
/*
    The pages...
   
    You could have different things for different pages...
    like what I got going with 'css' and 'title' for each page.
   
    That could be useful for things like javascript and other things
    that are page specific or things that other pages just don't need.
   
    I'm expecting here that each page would have it's own CSS and title
    element, so I coded in the process after the array that processes
    those things. If you are going to have something that is page
    specific and wouldn't be defined or neccessary to define elsewhere,
    you could use a conditional statement like I did with 'footer' and
    'image'.
*/
$pages = array(
            'index' => array('css' => '#div_name' => array('background-color' => '#fc0000',
                                                           'font-color' => '#000000'
                                                         ),
                                      'div[class].active_pages' => array('float' => 'right'
                                                         ),
                             'title' => 'Page Title for Index'
                            ),
            'contact'   => array('css' => 'p' => array('background-color' => '#fc0000',
                                                       'font-color' => '#000000'
                                                         ),
                                 'title' => 'Page Title for Contact',
                                 'image' => '<img src="path/to/img.png" alt="An image" />' // This would be written into the HTML part of the code... no need for additional PHP
                                ),
            'guestbook' => array('css' => 'span#name' => array('background-color' => '#fc0000',
                                                               'font-color' => '#000000'
                                                         ),
                                 'title' => 'Page Title for Guestbook',
                                 'footer' => 'Driven by Bigwebmaster © 2010 Bigwebmaster.com',
                                )
);
 
// Getting the page title for the pages
$page_title = (isset($pages[$page_name]['title'])) ? $pages[$page_name]['title'] : 'Welcome';
 
// Generating the CSS for this page
$css = null;
foreach($pages[$page_name]['css'] as $css_element => $css_components)
{
    $css .= $css_element . ' {\n';
    foreach($css_components as $css_rule => $css_value)
    {
        $css .= "     {$css_rule}: {$css_value};\n";
    }
    $css .= '}\n\n';
}
$css = trim($css);
 
// Generating the footer
$footer = (isset($pages[$page_name]['footer'])) ? $pages[$page_name]['footer'] : $footer;
 
?>