As you can read in @WebServer's answer there is a variety of template engines in node.
I want to give you an example of using one of them - EJS:
First install it:
npm install ejs
server.js:
var http = require('http');
var ejs = require('ejs');
var fs = require('fs');
http.createServer(function(req,res) {
res.writeHead(200, {'Content-Type': 'text/html'});
//since we are in a request handler function
//we're using readFile instead of readFileSync
fs.readFile('index.html', 'utf-8', function(err, content) {
if (err) {
res.end('error occurred');
return;
}
var temp = 'some temp'; //here you assign temp variable with needed value
var renderedHtml = ejs.render(content, {temp: temp}); //get redered HTML code
res.end(renderedHtml);
});
}).listen(80);
Your view might look like this:
<html>
<head>
</head>
<body>
My temperature: <%= temp %>
</body>
</html>
EJS also escapes temp (and other variables you pass to the view) for you, so you don't have to worry about XSS attacks.
Edit
You can also compile the template if you don't want to read the file on each request:
var http = require('http');
var ejs = require('ejs');
var fs = require('fs');
//we are not in a request handler so we may use readFileSync
var content = fs.readFileSync('index.html', 'utf-8');
var compiled = ejs.compile(content);
http.createServer(function(req,res) {
var temp = 'some temp';
res.writeHead(200, {'Content-Type': 'text/html'});
res.end(compiled({temp: temp}));
}).listen(80);
Edit 2 (answering your comment question)
Here is a simple example of using Express and AJAX:
server.js:
var http = require('http');
var express = require('express');
var app = express();
app.configure(function() {
app.set('view engine', 'ejs'); //tell Express we're using EJS
app.set('views', __dirname + '/views'); //set path to *.ejs files
app.use(app.router);
//put your static files (js, css, images) into /public directory
app.use('/public', express.static(__dirname + '/public'));
});
//get some server data for sending it to the client
var getData = function() {
return Math.random().toString();
}
app.get('/', function(req, res) {
//render index.ejs file
res.render('index', {val: getData()});
});
app.get('/ajax', function(req, res) {
res.send(getData());
});
http.createServer(app).listen(80);
views/index.ejs:
<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
<script src="/public/js/request.js"></script>
</head>
<body>
<h1>Val: <span id="val"><%=val%></span></h1>
<button id="loadRequest">Refresh</button>
</body>
</html>
public/js/request.js:
$(function() {
$('#loadRequest').click(function() {
$.get('/ajax', function(res) {
$('#val').text(res);
});
});
});
Hope this helps
