diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,10 @@
+0.3.0.5
+-------
+<https://github.com/mstksg/ghcjs-websockets/releases/tag/v0.3.0.5>
+
+*   Fixing `withURL` blocking when there is a javascript error on connection.
+    (Thanks to sztupi)
+
 0.3.0.4
 -------
 <https://github.com/mstksg/ghcjs-websockets/releases/tag/v0.3.0.4>
diff --git a/ghcjs-websockets.cabal b/ghcjs-websockets.cabal
--- a/ghcjs-websockets.cabal
+++ b/ghcjs-websockets.cabal
@@ -1,5 +1,5 @@
 name:                ghcjs-websockets
-version:             0.3.0.4
+version:             0.3.0.5
 synopsis:            GHCJS interface for the Javascript Websocket API
 description:
                      Documentation online at
diff --git a/src/JavaScript/WebSockets/Internal.hs b/src/JavaScript/WebSockets/Internal.hs
--- a/src/JavaScript/WebSockets/Internal.hs
+++ b/src/JavaScript/WebSockets/Internal.hs
@@ -210,7 +210,7 @@
     block   <- newMVar ()
     let conn = Connection socket queue waiters url closed block
     outp    <- newEmptyMVar
-    _       <- forkIO $ handleClose conn
+    _       <- forkIO $ handleClose conn outp
     -- TODO: Opening errors
     _       <- forkIO $ handleOpen conn outp
     return outp
@@ -231,8 +231,8 @@
                       _ <- ws_handleOpen (_connSocket conn)
                       putMVar connMVar conn
 
-handleClose :: Connection -> IO ()
-handleClose conn = do
+handleClose :: Connection -> MVar Connection -> IO ()
+handleClose conn connMVar = do
     connState <- connectionStateCode conn
     when (connState < 3) . handle handler $ do
       closeEvent <- ws_handleClose (_connSocket conn)
@@ -241,6 +241,7 @@
       reason     <- fmap fromJSString <$> getPropMaybe ("reason" :: Text) closeEvent
       let jsClose = JSClose wasClean code reason
       _ <- _closeConnection jsClose False conn
+      _ <- tryPutMVar connMVar conn
       return ()
   where
     -- TODO: any way to reasonably restore the handler?