jquery ajax returns error but is success

I have the following JS

function change_ajaxarea1(){
navigator.notification.activityStart();
$('#ajaxarea1').load('http://server.net/droiddev/backbone1/index.php/welcome/', function(){

navigator.notification.activityStop();
$('#ajaxarea1').css("height","auto");
//$('#ajaxarea1').css("overflow","hidden");
});

//navigator.notification.activityStart();
}


function postarticle(){

 $.post("http://server.net/droiddev/backbone1/", { headline: "John", article: "2pm" } );

 }


function addarticle(){

var headlinetemp=$('#headline').val();
var articletemp=$('#article').val();
$.ajax({
type:'POST',
dataType:'json',
url: "http://server.net/droiddev/backbone1/index.php/welcome/addarticle/",
data: { 'headline': headlinetemp, 'article': articletemp},
success:function(){
alert('success');
},
error:function(xhr){
alert(xhr.status);
}



});



}

and the following controller code :

  <?php 

class Welcome extends CI_Controller {


    public function index()
    {

    $data['query']=$this->site_model->get_last_ten_articles();
$this->load->view('partial1',$data);

    }

    public function addarticle(){

    $headline=$this->input->post('headline');
    $article=$this->input->post('article');
    $this->site_model->insert_entry($headline,$article);



    }
}

The addarticle() javascript ajax works and posts the vars to the server and into the db, however, javascript will then run the error function instead of the success functio开发者_开发问答n. The http response code is 200 which I thought would make it run the Success function. any suggestions?

---

You need to return json from controller, as this is what jQuery expects. You can return i.e.

{ success : true }

Or you could set html as data type (maybe it will work without content but you may need to return something)