function change_models (drop, id) {
  var ajax_search = new sack();
  var select = document.getElementById('car_model_'+id);

  if (drop) {
    select.options.length = 0;
    select.options[0] = new Option('Please wait...','');

    ajax_search.requestFile  = '/ajax/car_models.mhtml?manufacturer=' + drop;
    ajax_search.onCompletion = function () { load_selection('car_model_'+id,ajax_search) };
    ajax_search.runAJAX();

  } else {
    select.options.length = 0;
    select.options[0] = new Option('Please Wait...','');

    disable_field('car_model');
  }
}

function disable_field (id) {
  document.getElementById(id).disabled = true;
}

function load_selection (container, ajax_search) {  
  var select = document.getElementById(container);

  select.options.length = 0;
  select.options[0] = new Option('Please select...','');

  eval(ajax_search.response);

  select.disabled = false;
}


function enable_search (value, id) {
  if (value) {
    document.getElementById('model_search_'+id).disabled = false;
  }
}

function moveWindow (anchor){
  window.location.hash=anchor;
}