Cross-Origin Request Blocked, in Firefox.

Cross-Origin Request Blocked, in Firefox. On Chrome it's good.

===================

Hi;

I use ajax to update db.

It sends the form data and updates the DB well, however, the response doesn't work. Inspector says:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://webmoosh.com/plc_template_update. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing). It's open you can see it live ===> here <===

What am I doing wrong?

Thanks

function submit_form(form_id, form_box)
    {
        $("#"+form_id).submit(function(e) 
            {
                var url = '<?php echo base_url('plc_template_update');?>'; 
                $.ajax({
                   type: "POST",
                   url: url,
                   data: $("#"+form_id).serialize() + '&item_type=' + '<?php echo $item_type;?>' + '&item_id=' + '<?php echo $item_id;?>',
                   success: function(data)
                   {
                      $("#"+form_box).addClass('hide-me');
                      $("#success").removeClass('hide-me');
                      window.setTimeout(function(){
                        $("#success").addClass('hide-me');
                    }, 1000);
                   }
                 });
            e.preventDefault(); 
        });
    }

public function index()
        {
            if(!isset($_POST['item_id']) || !ctype_digit($_POST['item_id']))
                {
                    exit();
                }
            if($_POST['item_type']=='plc')
                {
                    //Uncomment when tests are over
                    // if(!$this->plc_library->is_this_plc_owner($_POST['item_id']))
                    //  {
                    //      exit();
                    //  }
                }       
            $data = array();
            foreach($_POST as $val=>$row)
                {
                    if($val!='item_id' && $val!='item_type' )
                        {
                            $data[$val]=$row;
                        }   
                }
            $this->db->where('id', $_POST['id']);
            $this->db->update('launch_page_elements', $data);
            http_response_code(200);
        }