function add_form(element, form) {
  var doc = document.getElementById(element);
  doc.innerHTML = "";
  $(element).insert(form, {'bottom': form});
}

function get(id)
{
  return document.getElementById(id);
}

function change_position(request) {
  object = request.responseText.evalJSON();
  if (object["result"] == null) {
    swap(object["item1"]["id"], object["item2"]["id"]);
  }
}

function swap(id1, id2) {
  var container1 = document.getElementById("item" + id1);
  var container2 = document.getElementById("item" + id2);
  var html = container1.innerHTML;
  container1.innerHTML = container2.innerHTML;
  container2.innerHTML = html;
  container1.id = "item" + id2;
  container2.id = "item" + id1;
}

function removeItem(request) {
  value = request.responseText.evalJSON();
  $("item" + value["id"]).remove();
  $("result").update(value["full_price"]);
  $("price_result").update(value["full_quantity"]);
}

function updateNumbers(request) {
  value = request.responseText.evalJSON();
  updateContainer(value);
}

function updateContainer(value) {
  $("number" + value["id"]).update(value["quantity"]);
  $("price" + value["id"]).update(value["price"]);
  $("quantity" + value["id"]).update(value["quantity"]);
  $("result").update(value["full_price"]);
  $("price_result").update(value["full_quantity"]);
}