PHP - 分页的最佳方式

Question

I am using this method for pagination:

I have a main holder and inside, I wrote:

$pag = $_REQUEST['pag'];

switch($pag) {
case 'register':
    include "inc/register.php";
    break;        
case 'noticia':
include "inc/login.php";
    break;
default:
    include "inc/main.php";
    }

How do professionals make this kind of dynamic pagination? How could I improve this?