$.ajax({
        method: "POST",
        contentType: 'application/json',
        dataType: 'json',
        url: "localhost:8000/test",
        data: JSON.stringify({user:"john", pass:"123"}),
        error: function () {
            alert('error');
        },
        success: function (data) {
            alert('success');
        }
    });

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

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

app.post('/login', function (req, res) {
  var user = req.body.user;
  var password = req.body.pass;
  if(user == 'john' && password == '123') {
    res.status(200);
  } else {
    res.status(401);
  }
});

app.listen(8000, function () {
  console.log('Example app listening on port 8000!');
});