{% if not flask_crossdomain_is_primary %}
<script type="text/javascript">
function performCrossDomainSessionCheck() {
  {% if not session.new %}
    var lastCheck = localStorage.getItem('last_session_check');
    if (lastCheck) {
      lastCheck = new Date(lastCheck);
      if (lastCheck.getTime() > (new Date().getTime() - 1000*3600*24*7)) {
        // less than a week since the last check
        return;
      }
    }
  {% endif %}
  function postAjax(data, primary_domain, success) {
    var xhr = new XMLHttpRequest();
    xhr.open('POST', primary_domain ? "{{ flask_crossdomain_url }}" : "{{ url_for('flask_crossdomain') }}");
    xhr.withCredentials = true;
    xhr.setRequestHeader('Content-Type', 'application/json');
    xhr.onload = function() {
      if (xhr.status === 200) {
        success(JSON.parse(xhr.responseText));
      }
    };
    xhr.send(JSON.stringify(data));
  }
  postAjax({
    action: "check",
    current_token: "{{ session.get('_token') }}",
    current_is_new: {{ session.new|lower }}
  }, true, function(data) {
    if (data.result === 'use_current') {
      localStorage.setItem('last_session_check', new Date().toISOString());
    } else if (data.result === 'replace') {
      postAjax({
        action: "replace",
        token: data.new_token
      }, false, function(data) {
        if (data.result === 'replaced') {
          localStorage.setItem('last_session_check', new Date().toISOString());
          window.location.reload();
        }
      });
    }
  });
}
performCrossDomainSessionCheck();
</script>
{% endif %}