detect coookies

cookies.js

// navigator.cookieEnabled cannot detect custom or nuanced cookie blocking
// configurations. For example, when blocking cookies via the Advanced
// Privacy Settings in IE9, it always returns true. And there have been
// issues in the past with site-specific exceptions.
// Don't rely on it.

// try..catch because some in situations `document.cookie` is exposed but throws a
// SecurityError if you try to access it; e.g. documents created from data URIs
// or in sandboxed iframes (depending on flags/context)
try {
  // Create cookie
  document.cookie = 'yamomsahoe=1';
  var ret = document.cookie.indexOf('yamomsahoe=') !== -1;
  // Delete cookie
  document.cookie = 'yamomsahoe=1; expires=Thu, 01-Jan-1970 00:00:01 GMT';
  return ret;
}
catch (e) {
  return false;
}
// https://github.com/Modernizr/Modernizr/blob/master/feature-detects/cookies.js

https://developer.mozilla.org/en-US/docs/Web/API/Document/cookie