Laravel AuthController not working when ajax request pass - php

Question

I am adapting the out-of-the-box AuthController in Laravel 5.2 to suit my needs. I want to implement login form using AJAX. For that I write the code. But when I click on login button then show 302 error and redirect. I don't know what is my mistake.
My JS
function do_login()
{
frm_name = 'userlogin';
username = $('#userlogin input[id=email]').val();
password = $('#userlogin input[id=password]').val();
_token = $('#userlogin input[id=_token]').val();
if(username == '' || password == '') {
$('#flashMessage').attr('class','alert alert-danger');
$('#flashMessage').html('Please specify Username and Password');
} else {
var param = 'username='+ username+ '&password='+ password +'&_token='+ _token;
$.ajax({
type : "POST",
datatype : "json",
url: "auth/login",
data : param,
success : function(data) {
data = JSON.parse(data);
if (data.status == 0) {
$('#myModallogin').modal('hide');
window.location.href = data.redirect_url;
}
if (data.status == 1) {
$('#flashMessage').attr('class','alert alert-danger');
$('#flashMessage').html(data.message);
} else {
onError(data.Error,'#'+ frm_name);
}
}
});
}
}
$(document).ready(function(){
$('#member_login').click(function() {
do_login();
});
});
My route
Route::auth();
Route::post('auth/login', 'Auth\AuthController#userLogin');
My AuthController
class AuthController extends Controller
{
/*
|--------------------------------------------------------------------------
| Registration & Login Controller
|--------------------------------------------------------------------------
|
| This controller handles the registration of new users, as well as the
| authentication of existing users. By default, this controller uses
| a simple trait to add these behaviors. Why don't you explore it?
|
*/
use AuthenticatesAndRegistersUsers, ThrottlesLogins;
/**
* Where to redirect users after login / registration.
*
* #var string
*/
//protected $redirectTo = '/';
/**
* Create a new authentication controller instance.
*
* #return void
*/
public function __construct() {
$this->middleware($this->guestMiddleware(), ['except' => 'logout']);
}
public function userLogin() {
$post_data = Request::all();
pr($post_data);exit;
}
}
My route is working properly because when I debug the routes for example Route::post('auth/login', function(){ echo 'aaaaaaaaaa'; }); so it display the aaaaaa. But when I called the function then show 302 error and redirect the page. I don't know what is my mistake. Please suggest me.