Add to my chat nodejs express another my function - node.js

Question

I have a basic chat working with NodeJS, express, and socket.io. I'm trying to add my own simple javascript function to the index.html. When I send message to other connected users, my function LoadRect() is draw a square but only on my web page. I want THE SAME square to be displayed on the other users screens with message. The message has random coordinates x, y, and random color (massege, x, y, c). Help me please. (Sorry for my english.)
index.html
<script src="/socket.io/socket.io.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<script>
var x;
var y;
var c;
function LoadRect() {
var e = document.createElement("div");
e.className = "rect";
document.body.appendChild(e);
e.appendChild(document.createTextNode("Square"));
e = e.style;
e.width = e.height='100px';
e.position = "absolute";
x = Math.floor(Math.random()*400+200)+'px';
y = Math.floor(Math.random()*400)+'px';
c = '#'+(Math.random()*0xFFFFFF<<0).toString(16);
e.left = x;
e.top = y;
e.background = c;
}
var socket = io.connect('http://localhost:8181');
socket.on('connect', function(){
socket.emit('adduser', prompt("What's your name?", "Guest"));
});
socket.on('updatechat', function (username, data) {
$('#conversation').append('<b>' + username + ':</b> '+ data + '</br>');
});
socket.on('updateusers', function(data) {
$('#users').empty();
$.each(data, function(key, value) {
$('#users').append('<div>' + key + '</div>');
});
});
$(function(){
$('#datasend').click( function() {
var message = $('#data').val();
$('#data').val('');
//LoadRect();
LoadRect();
socket.emit('sendchat', message, x, y, c);
});
$('#data').keypress(function(e) {
if(e.which == 13) {
$(this).blur();
$('#datasend').focus().click();
}
});
});
</script>
<b>USERS</b>
<div id="users"></div>
<div id="conversation"></div>
<input id="data" />
<input type="button" id="datasend" value="send" />
app.js
var express = require('express')
, app = express()
, http = require('http')
, server = http.createServer(app)
, io = require('socket.io').listen(server);
server.listen(8181);
app.get('/', function (req, res) {
res.sendfile(__dirname + '/index.html');
});
var usernames = {};
io.sockets.on('connection', function (socket) {
socket.on('sendchat', function (data, x, y, c) {
io.sockets.emit('updatechat', socket.username, data + ' [x=' + x + '; y=' + y + '; c=' + c +']');
});
socket.on('adduser', function(username){
socket.username = username;
usernames[username] = username;
socket.emit('updatechat', 'SERVER', ' connected');
socket.broadcast.emit('updatechat', 'SERVER', username + ', hello');
io.sockets.emit('updateusers', usernames);
});
socket.on('disconnect', function(){
delete usernames[socket.username];
io.sockets.emit('updateusers', usernames);
socket.broadcast.emit('updatechat', 'SERVER', socket.username + ', bye');
});
});