function select_zones_principales_onchange(evt){      
  /*
  choixZone(
    $('id_select_zones_principales').
      options[$('id_select_zones_principales').selectedIndex].
      value
    );
  if ($('id_select_zones_principales').
      options[$('id_select_zones_principales').selectedIndex].
      value==0){
      $('id_form_select_zone').submit();
  }
  */
  $('id_form_select_zone').submit();
  return true;
}
    
function select_zones_onchange(evt){
  $('id_form_select_zone').submit();
}
    
function choixZone(num){    
  var selectsZone = document.getElementsByName('select_zones');        
  for (var i=0 ; i<selectsZone.length ; i++ ){
    var selectZone = selectsZone[i];
    var idZone = parseInt(selectZone.id);        
    if (parseInt(num)>0){              
      if (idZone!=num){            
        selectZone.disabled=true;
        selectZone.style.display="none";            
      } else {            
        selectZone.disabled=false;
        selectZone.style.display="inline";                            
      }
    }
    else {
      selectZone.style.display="none";        
      selectZone.disabled=true;
    }
  }
}