index.html

<!DOCTYPE html>
<html lang="zh">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>sk5short one</title>
</head>
<body>
  <noscript>
    <h1>This site need javascript to redirect. If javascript is disabled then you need to view site source script tag. Address book is in there.</h1>
  </noscript>

  <script>
    let params = new URLSearchParams(location.search);
    let redirect = params.get('r')

    let defaultLink = 'https://www.sk5s.cyou/'
    let book = {
      'test' : 'https://lab.sk5s.cyou/'
    }
    if (redirect !== null && book[redirect] !== '' && book[redirect] !== undefined) {
      window.location.replace(book[redirect])
    } else {
      window.location.replace(defaultLink)
    }
  </script>
</body>
</html>