switch() for links like ?id=index problem

my code looks something like this: switch($id) { case "home": include("home.php"); break; } so links can be something like www.url.com?id=home I have also tried to use require instead of include When the desitred link is clicked, the page loads the new link, but also includes my index page taked onto the bottom of the new pages. what can I do to prevent this?