var hiProduktion = null;
var hiQualitaetsmerkmale = null;
var hiProdukte = null;
var hiAnwendung = null;
var hiInnovation = null;

function hishow(hi) {
  if (hi != null && hi.ready == true) {
    hi.show();
  }
}

function hihide(hi) {
  if (hi != null && hi.ready == true) {
    hi.hide();
  }
}

function show_hidden_image() {
    this.topImage.style.visibility = "visible";
    this.bottomImage.style.visibility = "visible";
}

function hide_hidden_image() {
    this.topImage.style.visibility = "hidden";
    this.bottomImage.style.visibility = "hidden";
}

function HiddenImage(topImage, bottomImage) {
    this.topImage = document.images[topImage];
    this.bottomImage = document.images[bottomImage];
    this.ready = true;
}
HiddenImage.prototype.show = show_hidden_image;
HiddenImage.prototype.hide = hide_hidden_image;

function initHiddenImages() {
    hiProduktion = new HiddenImage("produktion", "produktion_k");
    hiQualitaetsmerkmale = new HiddenImage("quali", "quali_k");
    hiProdukte = new HiddenImage("produkte", "produkte_k");
    hiAnwendung = new HiddenImage("anwendung", "anwendung_k");
    hiInnovation = new HiddenImage("innovation", "innovation_k");
}