How to create password and login validation (ajax + nodejs)?

Question

JavaScript

After submitting the data, the page reloads and displays the received data. In this case, it's OK.
How to make it so that if the status is 200, then the page is redirected to '/chat'?

ajax request script

$(document).ready(function() {
  
  $('#loginform').submit(function() {
    var form = $(this);
    var error = false;
    
    if (!error) {
      var data = form.serialize();
      
      $.ajax({
        url: '/login',
        method: 'POST',
        dataType: 'json'
        data: data,
        beforeSend: function(data) {
          form.find('input[type="submit"]').attr('disabled', 'disabled');
        },
        complete: function(data) {
          form.find('input[type="submit"]').prop('disabled', false);
        },
        statusCode: {
          200: function() {
            window.location.href = "/chat";
          },
          403: function(jqXHR) {
            var error = JSON.parse(jqXHR.responseText);
            alert(error.message);
          }
        },
        error: function (xhr, ajaxOptions, thrownError) {
          alert(xhr.status);
          alert(thrownError);
        }
      });
    } 
    
    return false;
  });
  
});

Path check

app.get('/login', function(req, res) {
    res.render('login');
  });
  
  app.post('/login', function(req, res, next) {
    var username = req.body.username;
    var password = req.body.password;
    
    console.log('Name: ' + username);
    console.log('Pass: ' + password);
    
    res.sendStatus(200);
  });
  
  app.get('/chat', function(req, res) {
    res.render('chat');
  });