function select_box(index) {
  var target_box;
  if (index == 1) {
    target_box = document.getElementById("recommended_car_box");
  }
  else if (index == 2) {
    target_box = document.getElementById("acquisition_info_box");
  }
  else {
    target_box = document.getElementById("new_stock_box");
  }
  document.getElementById("new_stock_box").style.display = "none";
  document.getElementById("recommended_car_box").style.display = "none";
  document.getElementById("acquisition_info_box").style.display = "none";
  target_box.style.display = "";
}