title: Cannot get value req.body.value in form
body: <p><strong>html form</strong></p>
  
  <pre><code>&lt;form method="post" action="/login"&gt;
      &lt;input type="text" name="user_vi" placeholder="User name vi" value="usernametest"&gt;
      &lt;input type="text" name="email_vi" placeholder="Email vi"&gt;
      &lt;br/&gt;
      &lt;input type="text" name="user_en" placeholder="User name en"&gt;
      &lt;input type="text" name="email_en" placeholder="Email en"&gt;
      &lt;input type="submit" value="Submit"&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p><strong>app.js</strong></p>
  
  <pre><code>var express = require('express');
  var bodyParser = require('body-parser');
  var app = express();
  // parse application/x-www-form-urlencoded
  app.use(bodyParser.urlencoded({ extended: false }));
  // parse application/json
  app.use(bodyParser.json());
  app.set('views', './views'); // specify the views directory
  app.set('view engine', 'ejs'); // register the template engine
  app.get('/', function(req, res) {
      res.render('index', { title: 'Home page', message: 'Home there!' })
  });
  app.get('/login', function(req, res) {
      res.render('login', { title: 'Login', message: 'Login there!' })
  });
  app.post('/login', function(req, res) {
      var lang = 'vi';
      var user_name = 'user_' + lang;
      //console.log(user_name);
      //result = "user_vi"
      console.log(req.body.user_name);
      //result = undefined
      console.log(req.body.user_vi);
      //result = 'usernametest'
      res.render('login', {
          title: 'Login',
          message: 'Login there!'
      });
  });
  app.listen(3000, function() {
      console.log('connect port 3000');
  });
  var lang = 'vi';
  var user_name = 'user_' + lang;
  //console.log(user_name);
  //result = "user_vi"
  //console.log(req.body.user_vi);
  //result = 'usernametest'
  console.log(req.body.user_name);
  //result = undefined
  </code></pre>
  
  <p>I cannot get value here (req.body.user_name). How can I get this ?</p>