Websocket onerror - ¿cómo leer la descripción del error?

He estado desarrollando un juego multijugador basado en navegador durante un tiempo y he estado probando la accesibilidad de diferentes puertos en varios entornos (oficina del cliente, wifi público, etc.). Todo va bastante bien, excepto una cosa: no puedo entender cómo leer el error no. o descripción cuando se recibe un evento de error.

El websocket del cliente se realiza en javascript.

Por ejemplo:

// Init of websocket
websocket = new WebSocket(wsUri);
websocket.onerror = OnSocketError;
...etc...

// Handler for onerror:
function OnSocketError(ev)
{
    output("Socket error: " + ev.data);
}

'salida' es solo una función de utilidad que escribe en un div.

Lo que obtengo es 'indefinido' para ev.data. Siempre. Y he estado buscando en Google, pero parece que no hay especificaciones sobre qué parámetros tiene este evento y cómo leerlo correctamente.

¡Se agradece cualquier ayuda!

El error que recibe Eventel onerrorcontrolador es un evento simple que no contiene dicha información :

Si se requirió que el agente de usuario fallara en la conexión WebSocket o la conexión WebSocket se cierra con perjuicio, active un evento simple llamado error en el objeto WebSocket.

Es posible que tenga más suerte al escuchar el closeevento, que es CloseEventy de hecho tiene una CloseEvent.codepropiedad que contiene un código numérico de acuerdo con RFC 6455 11.7 y una CloseEvent.reasonpropiedad de cadena.

Sin embargo, tenga en cuenta que CloseEvent.code(y CloseEvent.reason) están limitados de tal manera que se evitan el sondeo de la red y otros problemas de seguridad.

Junto con la respuesta de nmaier, como dijo , siempre recibirá el código 1006 . Sin embargo, si de alguna manera teóricamente recibiera otros códigos, aquí hay un código para mostrar los resultados (a través de RFC6455 ).

Casi nunca obtendrá estos códigos en la práctica, por lo que este código es prácticamente inútil

var websocket;
if ("WebSocket" in window)
{
    websocket = new WebSocket("ws://yourDomainNameHere.org/");

    websocket.onopen = function (event) {
        $("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "The connection was opened");
    };
    websocket.onclose = function (event) {
        var reason;
        alert(event.code);
        // See http://tools.ietf.org/html/rfc6455#section-7.4.1
        if (event.code == 1000)
            reason = "Normal closure, meaning that the purpose for which the connection was established has been fulfilled.";
        else if(event.code == 1001)
            reason = "An endpoint is \"going away\", such as a server going down or a browser having navigated away from a page.";
        else if(event.code == 1002)
            reason = "An endpoint is terminating the connection due to a protocol error";
        else if(event.code == 1003)
            reason = "An endpoint is terminating the connection because it has received a type of data it cannot accept (e.g., an endpoint that understands only text data MAY send this if it receives a binary message).";
        else if(event.code == 1004)
            reason = "Reserved. The specific meaning might be defined in the future.";
        else if(event.code == 1005)
            reason = "No status code was actually present.";
        else if(event.code == 1006)
           reason = "The connection was closed abnormally, e.g., without sending or receiving a Close control frame";
        else if(event.code == 1007)
            reason = "An endpoint is terminating the connection because it has received data within a message that was not consistent with the type of the message (e.g., non-UTF-8 [http://tools.ietf.org/html/rfc3629] data within a text message).";
        else if(event.code == 1008)
            reason = "An endpoint is terminating the connection because it has received a message that \"violates its policy\". This reason is given either if there is no other sutible reason, or if there is a need to hide specific details about the policy.";
        else if(event.code == 1009)
           reason = "An endpoint is terminating the connection because it has received a message that is too big for it to process.";
        else if(event.code == 1010) // Note that this status code is not used by the server, because it can fail the WebSocket handshake instead.
            reason = "An endpoint (client) is terminating the connection because it has expected the server to negotiate one or more extension, but the server didn't return them in the response message of the WebSocket handshake. <br /> Specifically, the extensions that are needed are: " + event.reason;
        else if(event.code == 1011)
            reason = "A server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.";
        else if(event.code == 1015)
            reason = "The connection was closed due to a failure to perform a TLS handshake (e.g., the server certificate can't be verified).";
        else
            reason = "Unknown reason";

        $("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "The connection was closed for reason: " + reason);
    };
    websocket.onmessage = function (event) {
        $("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "New message arrived: " + event.data);
    };
    websocket.onerror = function (event) {
        $("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "There was an error with your websocket.");
    };
}
else
{
    alert("Websocket is not supported by your browser");
    return;
}

websocket.send("Yo wazzup");

websocket.close();

Ver http://jsfiddle.net/gr0bhrqr/