diff --git a/lib/sockjs.dart b/lib/sockjs.dart
index 58694a3..6298b20 100644
--- a/lib/sockjs.dart
+++ b/lib/sockjs.dart
@@ -3,6 +3,7 @@ library sockjs_client;
 import "dart:html";
 import "dart:convert";
 import "dart:async";
+import "dart:js";
 
 import "src/events.dart" as event;
 import "src/utils.dart" as utils;
@@ -34,15 +35,7 @@ class Protocol {
   Protocol({this.create, this.enabled: true, this.roundTrips: 1, this.needBody: false});
 }
 
-// Keep dart2js happy ... no lazy initialization.
-Map<String, Protocol> _protocols;
-
-get PROTOCOLS {
-  if(_protocols == null) {
-    _protocols = {
-      "websocket": new Protocol(create:WebSocketTransport.create, enabled: WebSocketTransport.enabled, roundTrips: WebSocketTransport.roundTrips),
-      "xhr-streaming": new Protocol(create:XhrStreamingTransport.create, enabled: XhrStreamingTransport.enabled, roundTrips: XhrStreamingTransport.roundTrips)
-    };
-  }
-  return _protocols;
-}
\ No newline at end of file
+Map<String, Protocol> PROTOCOLS = {
+  "websocket": new Protocol(create:WebSocketTransport.create, enabled: WebSocketTransport.enabled, roundTrips: WebSocketTransport.roundTrips),
+  "xhr-streaming": new Protocol(create:XhrStreamingTransport.create, enabled: XhrStreamingTransport.enabled, roundTrips: XhrStreamingTransport.roundTrips)
+};
\ No newline at end of file
diff --git a/lib/src/transport/sender.dart b/lib/src/transport/sender.dart
index cc331a2..2b4b771 100644
--- a/lib/src/transport/sender.dart
+++ b/lib/src/transport/sender.dart
@@ -113,14 +113,14 @@ class JsonPGenericSender {
     form.submit();
 
     var readyStateChangeHandler = (e) {
-      if (iframe.readyState == 'complete') completed(null);
+      if (new JsObject.fromBrowserObject(iframe)["readyState"] == 'complete') completed(null);
     };
 
+    var subscriptions;
+
     completed = (e) {
-        if (iframe.on.error.isEmpty) return;
-        iframe.on.readyStateChange.remove(readyStateChangeHandler);
-        iframe.on.error.remove(completed);
-        iframe.on.load.remove(completed);
+        if (subscriptions == null) return;
+        subscriptions.forEach((s) => s.cancel());
 
         // Opera mini doesn't like if we GC iframe
         // immediately, thus this timeout.
@@ -131,9 +131,12 @@ class JsonPGenericSender {
         area.value = '';
         callback();
     };
-    iframe.on.error.add(completed);
-    iframe.on.load.add(completed);
-    iframe.on.readyStateChange.add(readyStateChangeHandler);
+
+    subscriptions = [
+      iframe.onError.listen(completed),
+      iframe.onLoad.listen(completed),
+      iframe.on["readyStateChange"].listen(readyStateChangeHandler)
+    ];
 
     //return completed;
   }
@@ -142,7 +145,7 @@ class JsonPGenericSender {
 createAjaxSender(AjaxObjectFactory xhrFactory)
     => (url, payload, callback([status, reason])) {
         AbstractXHRObject xo = xhrFactory('POST', '$url/xhr_send', payload);
-        xo.on.finish.add((e) {
+        xo.onFinish.listen((e) {
             callback(e.status);
         });
         return (abort_reason) {