AJAX call in expressJS - ajax

Question

I can't seem to get the AJAX call correct. There have been other QA that deal with the $.ajax() function but I'm trying to solve this with $.post().
When the form button is clicked the javascript at the head is executed, which includes a $.post(). The url /login is routed through and passed to loginPost function. There a response is determined and sent back to the javascript (right?). Instead, webpage renders the response (pass || fail).
Why isn't the response from the AJAX call being sent back to get processed?
This is a simple example that I am working with to get me better acquainted to how AJAX in expressJS and jQuery work. Any Help is greatly appreciated!
--views/login.jade
script(src='/_js/jquery-1.8.2.min.js')
script
$(document).ready(function(req, res) {
$('#login').submit(function() {
var formData = $(this).serialize();
console.log(formData);
$.post('/login', formdata, processData).error('ouch');
function processData(data, status) {
console.log(status);
console.log(data);
if (data == 'pass') {
$('#content').html('<p>You have successfully loggin in!</p>');
} else {
if (! $('#fail').length) {
$('#formFrame').prepend('<p id="fail">Incorrect login information. Please try again)</p>');
}
}
} //end processData
}); //end submit
}); //end ready
div.main
h1= title
div#formFrame
form(id='login', action='/login', method='POST')
p
label(for='username') Username:
input(id='username', type='text', name='username')
p
label(for='password') Password:
input(id='password', type='password', name='password')
p
input(id='button', type='submit', name='button', value='Submit')
--routes/index.js
app.post('/login', loginPost);
--routes/loginPost
module.exports.loginPost = function(req, res) {
var password = 'admin'
, username = 'user'
, data = req.body;
if (data.username == username && data.password == password) {
res.send('pass');
} else {
res.send('fail');
}
};

Answer 1

You still have to stop the <form> from submitting via its default action, which can be done with event.preventDefault():
$('#login').submit(function(evt) {
evt.preventDefault();
// ...
});
Otherwise, the <form> will redirect the page to its action (or back to the current address if no action was given), interrupting the $.post request.