Parse error: syntax error, unexpected ',', expecting '&' or T_VARIABLE in D:\wamp\www\CodeIgniter_2.1.0\application\mode

[eluser]salman@lee[/eluser]
<?php


class chat extends CI_controller

{
function chat()
{
parent::__construct();

$this->load->model('chat_model');
}

function index()
{

$this->view_data['chat_id'] = 1;

if(! $this->session->userdata('logged_in')) {

redirect('user/login');
}

$this->view_data['user_id'] = $this->session->userdata('user_id');

$this->view_data['page_title'] = 'chatting a web base chat app';

$this->view_data['page_content'] = 'view_chat';

$this->load_view('view_main', $this->view_data);


function ajax_add_chat_message()
{


/*thing that need to be past'ed to this function
*
*
*chat_id
*user_id
*chat_message_content
*
*
*
*
*/
$chat_id=$this->input->post('chat_id');

$user_id=$this->input->post('user_id');

$chat_message_contant=$this->input->post('chat_id', TRUE);

$this->chat_model->add_chat_message_content($chat_id, $user_id, $chat_message_content);
}
function ajax_get_chat_message()
{
$chat_id = $this->input->post('chat_id');

$chat_message = $this->chat_model->get_chat_message('$chat_id');

if ($chat_messages->num_rows()> 0)

//we have some chat let's return it

$chat_messages_html = '<ul>';

foreach ($chat_messages->result() as $chat_message)

$chat_messages_html .= '<li>' . $chat_message->chat_messge_content . '</li>';
}
$chat_messages_html .= '</ul>';

$result = array('status' => 'ok', 'content' => $chat_messages_html);

echo json_encode($result);

exit();
}
//else
/* {
$result = array('status' => 'ok', 'content' => '');

echo json_encode($result);

exit();

}
*/
}

?&gt;