var udid = {
    url: "",
    socket: null,
    connect: function (_url, _callback) {
        this.url = _url;
        var socket = this.socket;
        var that = this;
        if (socket && socket.readyState === socket.OPEN) {
            try {
                socket.send("Hi");
            } catch (ex) {
            }
            return;
        }

        if (socket && socket.readyState === socket.CONNECTING) {
            return;
        }

        if (socket && socket.readyState === socket.CONNECTING) {
            try {
                socket.close();
            } catch (e) {
            } finally {
                socket = null;
            }
        }

        if (socket && socket.readyState === socket.CLOSED) {
            socket = null;
        }

        try {
            socket = new WebSocket(this.url);
            socket.onopen = function (msg) {
                if (socket.readyState === socket.OPEN)
                    socket.send("Hi");
            };
            socket.onmessage = function (msg) {
                _callback(msg.data);
            };
            socket.onclose = function (msg) {
                that.close();
            };
            socket.onerror = function (msg) {
                that.close();
            };
        } catch (ex) {
            socket = null;
        }

    },
    close: function () {
        var socket = this.socket;
        if (socket) {
            try {
                socket.close();
            } catch (ex) {
            }
        }
        socket = null;
    }
};