function armTimer(response) { var timer = Components.classes["@mozilla.org/timer;1"] .createInstance(Components.interfaces.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, Components.interfaces.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.indexOf("first") != -1) { response.write("// first\n"); response.processAsync(); armTimer(response); } else if (request.queryString.indexOf("second") != -1) { response.write("// second\n"); setState("docwritepreloadssecond", "second"); } else { response.write("// third\n"); setState("docwritepreloadsthird", "third"); } }