Edit in JSFiddle

var onOpen = function() {
        console.log("Socket opened.");
        socket.send("Hi, Server!");
    },
    onClose = function() {
        console.log("Socket closed.");
    },


    onMessage = function(data) {
        console.log("We get signal:");
        console.log(data);
    },


    onError = function() {
        console.log("We got an error.");
    },

    
    socket = new WebSocket("ws://echo.websocket.org/");

socket.onopen = onOpen;
socket.onclose = onClose;
socket.onerror = onError;
socket.onmessage = onMessage;