Trying to do a redirect after a successful login. The login info is sent using ajax to the controller.

My controller code as below

public function login_controller_function()
{
    $this->load->model('login_model');
    if ($this->input->is_ajax_request())
    {
        $user_name=$this->input->post('username');
        $user_password = $this->input->post('password');
        $this->load->helper('url');
        $result = $this->login_model->verify_user($user_name,$user_password);
        //  echo 'user_logged_in';
        if(strcmp($result,'user_logged_in')==0)
        {
            redirect('welcome');

        }
    }
}

But it is not working at all. Anyone knows whats wrong?

Hi my html as requested. i am using twitter bootstrap as well

<li class="divider-vertical"></li>
<li><a href="#" id="login_btn">Login</a></li>
<li><a href="<?php echo base_url('register'); ?>">Register</a></li>

for the buttons so when i click the login button, a modal window will appear and ask for login info.

so when i click on the login button, my js code will send an ajax request

my js code as below

    /*Attempt register user jquery ajax*/
    $('#login').click(function(){ 

        var user_name = $('#loginHere').find('#user_name').val();

        var user_password = $('#loginHere').find('#login_pwd').val();

        if(user_name==""||user_password=="")
            return;

        var login_data = { username:user_name, password:user_password};


                $.ajax({
        type: "POST",
        dataType: "json",
        async: false,
        url:"login_register/login_controller_function",
        data: login_data,
        success: function(data) {
            if(data.login)
            {
                alert(data.redirect);
                window.location.replace(data.redirect);

            }
            else if(!data.login)
            {
                alert('data login not true');
            }
        },
        error:function(data){
            alert('ajax error');
        }
    });
    });
});