每一次打开页面随机运作一段代码。其他几段不运行的代码

$rd = rand(0,5);

switch($rd){
case 1:
    echo "1111";
    break;
case 2:
    echo "2222";
    break;
case 3:
echo "3333";
case 4:
    echo "4444";
    break;

default:
    echo "sorry";
    break;
}