jQuery JSON not passing data to Ci properly - php

Question

The script below works as far as i can tell:
<script type="text/javascript" language="javascript">
$(document).ready(function() {
$('#add').bind('keypress', function(e) {
if(e.keyCode == 13){
var add = $("#add").val();
$.ajax({
type: "POST",
dataType: "JSON",
url: "<?php echo site_url("home/jsonAddData"); ?>",
data: add,
json: {title_posted: true},
success: function(data){
if(data.title_posted == true) { // true means data was successfully posted.
$("#success").append("Success").fadeIn(400);
} else if(data.title_posted == false) { // false means data failed to post.
$("#success").append('Failure').fadeIn(400);
}
}
});
}
});
});
</script>
The problem I'm experiencing with the code below is that the mysql insetion query just wont work. It creates the row in the table and auto-increments but for some odd reason it wont pass the 'var add' in the Javascript above to the Ci script below and perform an insertion in the db. Any thoughts or ideas?
<?php
class home extends CI_Controller {
function __construct() {
parent::__construct();
}
function index() {
$data = array();
$data['lists'] = $this->displayList();
$this->load->view('home', $data);
}
function displayList() {
$str = '';
$query = $this->db->query("SELECT * FROM data");
foreach ($query->result() as $row) {
$b = '<input name="completed" type="checkbox" />';
$a = $row->title . "<br>";
$str .= $b.$a;
}
return $str;
}
function jsonAddData() {
if($this->input->is_ajax_request()) {
$title = $this->input->post('title');
$query = $this->db->query("INSERT INTO data (title) VALUES ('$title')");
header('Content-type:application/json');
if($query) echo json_encode(array('title_posted' => true));
else echo json_encode(array('title_posted' => false));
}
}
}
?>

Answer 1

In
$.ajax({
...
data: {title: add}
Not just a string