PHP specified URL jump code example_PHP tutorial

$s = $_SERVER['QUERY_STRING'];
if ($s == "http://www.baidu.com");
{
$s = "http://www.qq.com";
}
if ($s == "http://www.hao123.com");
{
$s = "http://www.bkjia.com";
}
header("Location:".$s."");
?>

http://www.bkjia.com/PHPjc/371589.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/371589.htmlTechArticle? $s = $_SERVER['QUERY_STRING']; if ($s == http://www.baidu.com); { $s = http://www.qq.com; } if ($s == http://www.hao123.com); { $s = http://www.bkjia.com; } header(Location:.$s.)...