fune/parser/htmlparser/tests/mochitest/file_bug543062.sjs

var timer;

function armTimer(response) {
  timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
  timer.initWithCallback(
    function() {
      if (
        getState("docwritepreloadssecond") == "second" &&
        getState("docwritepreloadsthird") == "third"
      ) {
        response.write(
          "ok(true, 'Second and third scripts should have started loading while the first one is loading');"
        );
        response.finish();
      } else {
        armTimer(response);
      }
    },
    20,
    Ci.nsITimer.TYPE_ONE_SHOT
  );
}

function handleRequest(request, response) {
  response.setHeader("Cache-Control", "no-cache", false);
  response.setHeader("Content-Type", "text/javascript", false);
  if (request.queryString.includes("first")) {
    response.write("// first\n");
    response.processAsync();
    armTimer(response);
  } else if (request.queryString.includes("second")) {
    response.write("// second\n");
    setState("docwritepreloadssecond", "second");
  } else {
    response.write("// third\n");
    setState("docwritepreloadsthird", "third");
  }
}