npm install socket.io --save

var app = express();

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

app.use(function(req, res, next){
 res.io = io;
 next();
});

var port = 3000;
app.set('port', port);
server.listen(port);

io.on('connection', function (socket) {
 socket.emit('news', { hello: 'world1' });
 socket.on('my other event', function (data) {
  console.log(data);
 });
});

<script src='javascripts/socket.io-1.4.5.js'></script>
var socket = io.connect("//localhost:3000");
socket.on('news', function (data) {
  console.log(data);
  alert(data);
  socket.emit('my other event', { my: 'data' });
});

router.get('/', function(req, res, next) {
  //只有当前页面可以获得
  res.io.on('connection', function(socket) {
    socket.emit('news', {
      hello: 'world'
    });
    socket.on('my other event', function(data) {
      console.log(data);
    });
  });
  //所有页面都可以获得
  var io = require("../app").io;
  io.emit("news",{hello:"myworld"});
  res.render("pclogin.ejs", {});
});