src/third_party/web_platform_tests/XMLHttpRequest/setrequestheader-header-allowed.htm

<!doctype html>
<html>
  <head>
    <title>XMLHttpRequest: setRequestHeader() - headers that are allowed</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <link rel="help" href="https://xhr.spec.whatwg.org/#the-setrequestheader()-method" data-tested-assertations="/following::ol/li[6] /following::ol/li[7]" />  
  </head>
  <body>
    <div id="log"></div>
    <script>
      function request(header) {
        test(function() {
          var client = new XMLHttpRequest()
          client.open("POST", "resources/inspect-headers.py?filter_value=t1, t2", false)
          client.setRequestHeader(header, "t1")
          client.setRequestHeader(header, "t2")
          client.send(null)
          assert_equals(client.responseText, header.toLowerCase() + ",")
        }, document.title + " (" + header + ")")
      }
      request("Authorization")
      request("Pragma")
      request("User-Agent")
      request("Content-Transfer-Encoding")
      request("Content-Type")
      request("Overwrite")
      request("If")
      request("Status-URI")
      request("X-Pink-Unicorn")
    </script>
  </body>
</html>