const express = require('express'),
      app = express(),
      bodyParser = require('body-parser');

// support parsing of application/json type post data
app.use(bodyParser.json());

//support parsing of application/x-www-form-urlencoded post data
app.use(bodyParser.urlencoded({ extended: true }));

app.get('/',function(req,res){
    var inputCity= req.body.city;   //city is the name specified in in put tag i.e <input name="city">
  console.log(inputCity);
});


/*
bodyParser.text - pass all the requests into text.
bodyParser.json - parse data into JSON format.
bodyParser.urlencoded - commonly used when getting data posted from
*/

$ npm install body-parser

var express = require('express')
  var bodyParser = require('body-parser')
  var app = express()
  // parseapplication/x-www-form-urlencoded
  app.use(bodyParser.urlencoded({ extended: false }))
  // parse application/json
  app.use(bodyParser.json()) app.use(function (req, res) {  res.setHeader('Content-Type', 'text/plain')  res.write('you posted:\n')  res.end(JSON.stringify(req.body, null, 2))})

<script>
const bodyParser = require("body-parser");

app.use(bodyParser.urlencoded({extended:true}));
  
app.post("/", function(req, res){
  let firstName = req.body.fNAME;
  
});
</script>

<input type="text" name="fNAME" placeholder="First Name">

var bodyParser = require('body-parser')

// parse application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: false }))
 
// parse application/json
app.use(bodyParser.json())

npm install body-parser
const bodyParser = require('body-parser')