CSS & JS Through PHP

<?php
$_GET['cache'] = isset($_GET['cache']) && ctype_alpha($_GET['cache']) ? trim($_GET['cache']) : 'cache';

switch ($_GET['cache']) {
    case 'styles' : init_css();
        break;
    case 'scripts': init_js();
        break;
    default :
        echo "Script requires an action.";
}

function init_css() {
    header("Content-type: text/css");
    $bgcolor = "#000";
    ?>
    body
    {
        background-color: <?php echo $bgcolor; ?>

    }
<?
}
?>
<?php
function init_js() {
    header("Content-type: text/javascript");
?>
  alert('Javascript through php file.');
<? }
?>

<link rel="stylesheet" href="cache.php?cache=styles" type="text/css" />
<script src="cache.php?cache=scripts" type="text/javascript"></script>