If I understand correctly, you want to check if the Cookies are enabled on the Authentication page.
You can use JavaScript code.
Please follow these steps:
1) Open your Authentication, select Custom in the Setup options field.
2) In the Element section, add a Header&Footer element (the Plus button in the header of the section).
3) To the Footer, add the JavaScript code:
<script type='text/javascript'>
function are_cookies_enabled()
{
var cookieEnabled=(navigator.cookieEnabled)? true : false;
if (typeof navigator.cookieEnabled=="undefined" && !cookieEnabled)
{
document.cookie="testcookie";
cookieEnabled=(document.cookie.indexOf("testcookie")!=-1)? true : false;
}
if (!cookieEnabled)
alert('Cookies are disabled!');
}
window.onload=are_cookies_enabled;
</script>
You can enter your text instead of "Cookies are disabled".