php include question

[odetron]

$pg = 1;
$_GET[$pg];
//Draws the page data
if ($pg == 1)
{ 
include("news1.inc.html");
}

if ($pg == 2)
{
include("news2.inc.html");
} 

what i whant this code to do is change the site content depending on what the url is. like index.php?pg=2 would bring up hello world 2 and just index. php would bring up hello world. but on both i keep getting the one for $pg = 1 why won't this work?

[Jessica]

if(isset($_GET['pg']){
   $pg = $_GET['pg'];
}else{
   $pg = 1;
}

[trq]

<?php
  if (isset($_GET['pg'])) {
    $pg = $_GET['pg'];
    switch ($pg) {
      case 1: include "news1.inc.html" ; break;
      case 2: include "news2.inc.html" ; break;
      default: include "news1.inc.html" ; break;
    }
  }
?>