How to call certain div class when certain condition is done?

[eluser]Michal1[/eluser]
Hello guys,

I have pretty basic and stupid question. How to show certain div class when some condition is done. Let say in my view I have

Code:

<div class="msg msg-ok">
   <p><strong>Your file was uploaded succesifully!</strong></p>
   <a href="#" class="close">close</a>
  </div>

and in my controller i have function which handles adding articles.

Code:

public function add_thread()
{
  
  
  $data = array(
  'name' =>$this->input->post('name'),
  'text'=>$this->input->post('text')
  );
  
  $this->site_model->insert_thread($data);
  
  redirect ('site');
  
}

and after this is done I want to display that msg msg-ok from my view. How to do that please?