var Bilder = function(container) {
  var container = document.getElementById(container);
  var current = 0;
  if (container) {
    var _images = container.getElementsByTagName('img');
    var images = [];
    var image;
    for (var i = 0, l = _images.length; i < l; i++) {
      image = new Image();
      image.src = _images[i].src;
      image.alt = _images[i].alt;
      images.push(image);
    }
    while (container.hasChildNodes()) {
      container.removeChild(container.firstChild);
    }
    image = new Image();
    image.src = images[current].src;
    container.appendChild(image);
    var schalter = document.createElement('div');
    var prev = document.createElement('button');
    var next = document.createElement('button');

    prev.onclick = function(m) { return function(event) { m.prev.call(m, event); } }(this);
    next.onclick = function(m) { return function(event) { m.next.call(m, event); } }(this);

    prev.appendChild(document.createTextNode('vorheriges'));
    next.appendChild(document.createTextNode('nächstes'));
    schalter.appendChild(prev);
    schalter.appendChild(document.createTextNode(' '));
    schalter.appendChild(next);
    container.appendChild(schalter);
    schalter.appendChild(document.createTextNode(' '));
    var label = document.createTextNode(images[current].alt);
    schalter.appendChild(label);
  }

  this.next = function(event) {
    if ((current + 1) < images.length) {
      current++;
      image.src = images[current].src;
      label.nodeValue = images[current].alt;
    }
  };

  this.prev = function(event) {
    if (current > 0) {
      current--;
      image.src = images[current].src;
      label.nodeValue = images[current].alt;
    }
  };
};


(function() {
  window.onload = function() {
    var bilder = new Bilder('bilder');
  };
})();