• Router: Even they're in same domain, it shows different page when they have different url. it shows different result as the information after "path"

when path is '/', it's when client searched domain address.

• HTTP method
• GET: shows specific resource. this request only "get" data. (response.send)
• HEAD: same request with "GET" method but do not include response itself.
• POST: "send" entity to specific resource.
• DELETE: delete specific resource.
• CONNECT: make tunnel with final resource

const express = require('express');
const app = express()
const port = 3000

app.get('/', (req, res) => {
    res.send("INDEX <a href='/detail'>to DETAIL</a>");
});

app.get('/detail', (req, res) => {
    res.send("DETAIL PAGE");
});

app.listen(port, () => {
    console.log(`Listening at <http://localhost>:${port}`);
});