尝试构建基于模板的php具有获取和发布的问题

I am building my first real php web app. as many you know this requires building LOTS of pages.

in attempting to streamline the repetitive stuff i placed most of my stuff within a content.php page which looks like this

<?php include_once ('config3.inc');?>
<?php if(isset($_GET['p'])){
    $page = $_GET['p'];

}else {
    $page ='';
}
?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" dir="ltr" lang="en">

<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title><?php echo $_SERVER['PHP_SELF'];?></title>
    <?php include('styles.inc');?>

   <?php include('api.inc'); ?>
   <?php include('scripts.inc');?>
</head>

<body>
<div id="container">
    <?php include ('header.inc');?>

    <div><!-- Content -->
    <?php include  ('./content/'.$page);?>
    </div>

</div><!-- end container -->
<!-- Footer -->
<?php include ('footer.inc');?>
</body>
</html>

This way when I want to call up a page I go to www.domain.com/content.php?p=pagename.php and it will "wrap" everything in the correct style sheets container and footer etc.

had been working well until I started making my CRUD pages requiring that pagename use POST data.

Is there a better approach for this or do I need to scrap this approach entirely?