<?PHP
$smart = "crikey";

switch ($smart) {
     case "Crikey":
         echo "Crikey";
         break;
     case "Hund":
         echo "Hund";
         break;
     case "Kat":
         echo "Kat";
         break;
     default:
         echo "Alt Andet";
}
?>

上面的代码打印“Alt Andet”,但我想比较字符串不区分大小写并打印“Crikey”.我怎样才能做到这一点？