cross.html

<!DOCTYPE html>
<script>
var queryString = location.search;

if (queryString && queryString.charAt(0) === '?') {
  // Cross-Origin fetch with a custom header.
  console.log("################################ cross.html trying fetch");
  //fetch(queryString.substring(1)+"foo.html", {headers: {'X-Custom-Header2':'foobar'}});
  fetch(new Request(queryString.substring(1)+"service_worker/cross_site_xfer_scope/cross_site_xfer_confirm_via_serviceworker.html",
        {headers: {'X-Custom-Header2':'foobar'}})).then(function(data) {
          console.log("fetch returned "+ data);
        });
} else {
  console.log("################################ cross.html trying fetch2");
  fetch("https://www.wikipedia.org/portal/wikipedia.org/assets/img/Wikipedia-logo-v2@2x.png",
        {headers: {'X-Custom-Header2':'foobar'}});
}

</script>