Autocomplete hidden a part of response

Autocomplete hidden a part of response

Hi , sorry for english thi is a part of my function to get response of autocomplete :

  2. $arr_result[] = $row->comune.' ('.$row->sigla.') <span style="display:none;"> ['.$row->id.']<span>';
  3. echo json_encode($arr_result);            
  4.                                                                                                                                

in my input field i want hide the value in the span but the response is :

Alzano Lombardo (BG) <span style="display:none;"> [1934]<span>

HOw can i hide the span ?