<!doctype html>
<html>
<head>
</head>
<body>
<script type="text/javascript">
  if (window.opener && window.opener.oauth2 && window.opener.oauth2.__doLogin) {
    if (location.hash.length !== 0) {
      window.opener.oauth2.__doLogin(location.hash);
    } else {
      window.opener.oauth2.__doLogin(location.search);
    }
  } else {
    document.body.innerText =
        "Your browser seems to be stopping this window from communicating with the main window.";
  }
</script>
</body>
</html>

<!doctype html>
<html>
<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, user-scalable=no, shrink-to-fit=no">
</head>
<body>
<script type="text/javascript">
  if (window.opener && window.opener.oauth2 && window.opener.oauth2.__doLogin) {
    if (location.hash.length !== 0) {
      window.opener.oauth2.__doLogin(location.hash);
    } else {
      window.opener.oauth2.__doLogin(location.search);
    }
  } else {
    document.body.innerText =
        "Your browser seems to be stopping this window from communicating with the main window.";
  }
</script>
</body>
</html>

Add 'viewport' meta to have a readable message on Mobile device
Add 'viewport' meta to have a readable message on Mobile device
