third_party/web_platform_tests/XMLHttpRequest/open-referer.htm

<!doctype html>
<html>
  <head>
    <title>XMLHttpRequest: open() - value of Referer header</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <link rel="help" href="https://xhr.spec.whatwg.org/#the-open()-method" data-tested-assertations="/following::ol[1]/li[2]/ol[1]/li[4]" />
  </head>
  <body>
    <div id="log"></div>
    <script>
      test(function() {
        var client = new XMLHttpRequest()
        client.open("POST", "resources/inspect-headers.py?filter_name=referer", false)
        client.send(null)
        assert_equals(client.responseText, "referer: "+location.href+'\n')
      })
    </script>
  </body>
</html>