title: ServiceWorkers and cookies
body: <p>Our serviceworker does one thing: It forwards every request to the server and when the server is offline the serviceworker catches the exception and displays an "offline" page.</p>
  
  <p>The documentation says that in order for serviceworkers to send cookies one needs to define the credentials, like this:</p>
  
  <pre><code>fetch(url, {
      credentials: "same-origin"
  }).then(...).catch(...);
  </code></pre>
  
  <p>QUESTION: We do not set credentials, so why is our server still receiving the cookies when we use this code:</p>
  
  <pre><code>self.addEventListener('fetch', function(event) {
      event.respondWith(
          fetch( event.request ).catch(function(error) {
                  return caches.open('offline').then(function(cache) {
                      return cache.match("/offline.html");
              });
          })
      );
  });
  </code></pre>
  
  <p>PS: We are happy about that but not sure why it is working</p>