fix readystate event handler invocation
diff --git a/weinre.web/modules/weinre/common/WebSocketXhr.coffee b/weinre.web/modules/weinre/common/WebSocketXhr.coffee
index 6e10488..456ba91 100644
--- a/weinre.web/modules/weinre/common/WebSocketXhr.coffee
+++ b/weinre.web/modules/weinre/common/WebSocketXhr.coffee
@@ -201,7 +201,7 @@
         xhr = (if XMLHttpRequest.noConflict then new XMLHttpRequest.noConflict() else new XMLHttpRequest())
         xhr.httpSocket = this
         xhr.httpSocketHandler = handler
-        xhr.onreadystatechange = _xhrEventHandler
+        xhr.onreadystatechange = -> _xhrEventHandler xhr
 
         HookLib.ignoreHooks ->
             xhr.open method, url, true
@@ -212,8 +212,7 @@
             xhr.send data
 
 #-------------------------------------------------------------------------------
-_xhrEventHandler = (event) ->
-      xhr = event.target
+_xhrEventHandler = (xhr) ->
       return unless xhr.readyState == 4
 
       xhr.httpSocketHandler.call xhr.httpSocket, xhr