Connecting to TCP Socket from browser using javascript

You can use HTML5 Web Sockets:

var connection = new WebSocket('ws://IPAddress:Port');
connection.onopen = function () {
  connection.send('Ping'); // Send the message 'Ping' to the server
};

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See . Haven't used it myself. Been more than 3 years since last update (as of 26/6/2014).

From the documentation:

<script type='text/javascript'>
    // Host we are connecting to
    var host = 'localhost';
    // Port we are connecting on
    var port = 3000;

    var socket = new jSocket();

    // When the socket is added the to document
    socket.onReady = function(){
            socket.connect(host, port);
    }

    // Connection attempt finished
    socket.onConnect = function(success, msg){
            if(success){
                    // Send something to the socket
                    socket.write('Hello world');
            }else{
                    alert('Connection to the server could not be estabilished: ' + msg);
            }
    }
    socket.onData = function(data){
            alert('Received from socket: '+data);
    }

    // Setup our socket in the div with the id="socket"
    socket.setup('mySocket');
</script>