Socket.io > Simple server to client message

my problem between socket.io and HTML5

Javascript Server:

var app = require('express')();
var http = require('http').Server(app);
var io = require('socket.io')(http);

app.get('/', function(req, res){
res.sendfile('index.html');
});
io.on('connection', function(socket){
socket.emit('news','Hello');  
});
http.listen(3000, function(){
console.log('listening on *:3000');
});

HTML5:

<html>
<head>
    <meta charset="UTF-8">
    <title>My Title</title>
</head>
<body>
        <input type="button" id="getButton" value="Get Rooms">
        <script src="/socket.io/socket.io.js"></script>
        <script src="http://code.jquery.com/jquery-1.11.1.js"></script>
        <script>
            var socket = io();
            $("#getButton").click(function(){
              socket.on('news',function(data){
              alert(data);
              });
            });
         </script>
</body>
</html>

When I click on the button (ID: getButton) I dont get an alert. The server ist working and I can access the page without any problems.

Iam currently a newbie in socket.io/javascript (installed yesterday), if you have good informative pages about socket.io please post the link under this topic, thanks.

best regards

You're emitting the news message as soon as you connect, so it has already fired by the time you click your button. Try changing your code to this and you should see your alert:

var socket = io();
socket.on('news', function(data) {
    alert(data);
});

You could trigger the event on a button with something like this:

Server:

io.on('connection', function(socket) {
    //socket.emit('news','Hello');  
});

// Return the news when it's requested
io.on('giveMeNews', function(socket) {
    socket.emit('news', 'Here is your news');
});

Client:

// Listen for the news message
socket.on('news', function(data) {
    alert(data);
});

// Request news from the server
$("#getButton").click(function() {
    socket.emit('giveMeNews');
)};