พอดีผมตรวจโค้ดในเว็บที่จ้างเขาทำ เจอโค้ดแปลก ๆ ครับมันคืออะไร ?

<?php 
session_start();
ini_set('display_errors', 'On');
//ob_start("ob_gzhandler");
error_reporting(E_ALL);

// database connection config
$dbHost = 'localhost';
$dbUser = 'root';
$dbPass = '1234';
$dbName = 'sql';


$email = "[email protected]";

ini_set("memory_limit","20M");
// setting up the web root and server root for
// this shopping cart application
$weburl = "http://www.XXXXX.net"; //บรรทัดนี้ คืออะไรครับ ???????????????????
$thisFile = str_replace('\\', '/', __FILE__);
$docRoot = $_SERVER['DOCUMENT_ROOT'];

$webRoot  = str_replace(array($docRoot, 'library/config.php'), '', $thisFile);
$srvRoot  = str_replace('library/config.php', '', $thisFile);

define('WEB_ROOT', $webRoot);
define('SRV_ROOT', $srvRoot);

// these are the directories where we will store all
// category and product images
define('CATEGORY_IMAGE_DIR', 'imgs/cat/');
define('PRODUCT_IMAGE_DIR',  'imgs/cat2/');
define('BANNER_IMAGE_DIR',  'imgs/banner/');

define('ACTIVITY_IMAGE_DIR', 'imgs/productspost/');
define('ACTIVITY_FILE_DIR', 'imgs/Activity/');
define('PERSON_IMAGE_DIR', 'imgs/Person/');


// some size limitation for the category
// and product images

// all category image width must not 
// exceed 75 pixels
define('MAX_Activity_IMAGE_WIDTH', 90);
define('MAX_PERSON_IMAGE_WIDTH', 90);


// do we need to limit the product image width?
// setting this value to 'true' is recommended
define('LIMIT_PRODUCT_WIDTH',     true);

// maximum width for all product image
define('MAX_PRODUCT_IMAGE_WIDTH', 600);
define('MAX_SLIDE_IMAGE_WIDTH', 720);
define('THUMBNAIL_WIDTH_BAN', 140);

// maximum width for all product image
define('LIMIT_BANNER_WIDTH',     true);
define('MAX_BANNER_IMAGE_WIDTH', 120);
define('THUMBNAIL_BANNER_WIDTH', 120);


// the width for product thumbnail
define('THUMBNAIL_WIDTH',         100);
define('THUMBNAIL_ACTIVITY_WIDTH',         100);

if (!get_magic_quotes_gpc()) {
	if (isset($_POST)) {
		foreach ($_POST as $key => $value) {
			$_POST[$key] =  trim(addslashes($value));
		}
	}
	
	if (isset($_GET)) {
		foreach ($_GET as $key => $value) {
			$_GET[$key] = trim(addslashes($value));
		}
	}	
}

// since all page will require a database access
// and the common library is also used by all
// it's logical to load these library here
require_once 'database.php';
require_once 'common.php';


// get the shop configuration ( name, addres, etc ), all page need it
//$shopConfig = getShopConfig();

function get_customer_reviews($isbn)
	{
	$link = "http://astore.amazon.co.uk/32.lcd.tv-21/detail/".$isbn; //บรรทัดนี้ด้วย ??????
	$xfile = fopen($link,"r"); 
	
	// link from internet 
	while(!feof($xfile)){
	 $char = fread($xfile,5000);
	 $txt .= $char;
	 
	 }
	 
	 $xtx = str_replace('"','',$txt);
	 $x = str_replace("'","",$xtx);
	 $start = '<div id=customerReviews>';
	 $txtarr = explode($start,$x);
	 $content = explode('</div>',
	 $txtarr[1]);
	 echo $content[0];
	 }
	 
?>