Checking transmission of Beacons involving cookies. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS navigator.sendBeacon("resources/save-beacon.php?name=cookie", "Blip"); is true PASS Beacon sent successfully PASS Content-Type: text/plain;charset=UTF-8 PASS Cookie: hello=world PASS Origin: http://127.0.0.1:8000 PASS Referer: http://127.0.0.1:8000/blink/sendbeacon/beacon-cookie.html PASS Request-Method: POST PASS Length: 4 PASS Body: Blip PASS PASS successfullyParsed is true TEST COMPLETE