Using node.js to serve up basic web page with CSS and JS includes

Question 1

Simple: you're setting the Content-Type header to text/html, always. Also, it will always serve your index.html file. Look:

fs.readFile('index.html', function (err, html) {
    if (err) {
        throw err; 
    }       
    http.createServer(function(request, response) { 
        response.writeHeader(200, {"Content-Type": "text/html"});  // <-- HERE!
        response.write(html);  // <-- HERE!
        response.end();  
    }).listen(1337, '127.0.0.1');
});

You should parse the URL, look up what file you want to require, read its contents and write them to the response if it exists, otherwise serve an 404 error. Also, you'll need to set the correct headers.

So, do you still want to do it at your own?
At least, try something like send, which is a basic static file server.

Question 2

Rather than pointing contentType to text/html, You can do some thing like this using path module

var filePath = req.url;
if (filePath == '/')
  filePath = '/index.html';

filePath = __dirname+filePath;
var extname = path.extname(filePath);
var contentType = 'text/html';

switch (extname) {
    case '.js':
        contentType = 'text/javascript';
        break;
    case '.css':
        contentType = 'text/css';
        break;
}


fs.exists(filePath, function(exists) {

    if (exists) {
        fs.readFile(filePath, function(error, content) {
            if (error) {
                res.writeHead(500);
                res.end();
            }
            else {                   
                res.writeHead(200, { 'Content-Type': contentType });
                res.end(content, 'utf-8');                  
            }
        });
    }

Question 3

You are creating a web server that does one thing and one thing only irrespective of what path or parameters are sent: it serves your HTML file index.html with MIME type text/html.

The requests for CSS files are relative path requests, i.e. when the web browser sees the instruction to load css/plugin.css it calls your web server with a new path; but your web server ignores the path and just returns index.html again with MIME type text/html. Your web browser throws errors about the wrong MIME type but what it didn't tell you was that you just loaded index.html again.

To confirm for yourself click on the following link: http://127.0.0.1:1337/css/plugin.css

Question 4

Your server is responding to all request with a unique response... When the browser request for CSS and Scripts, your server do the only thing he knows !!!