var ids = new Array();
var images = new Array();
var descriptions = new Array();
var workId = 0;

function back() {
  --idx;
  if(idx < 0) idx = idx + images.length;
  document.getElementById("counter").innerHTML = (idx+1) + "/" + images.length;
  setImage(idx);
}

function next() {
  idx = ++idx % images.length;
  document.getElementById("counter").innerHTML = (idx+1) + "/" + images.length;
  setImage(idx);
}

function setImage(idx) {
  var image = document.getElementById("image");
  image.src = images[idx];
  var description = document.getElementById("description");
  description.innerHTML = descriptions[idx];
  workId = ids[idx];
}

function addToLightbox() { // override lightbox function   
  var f = document.forms[0];
  f.hidWorkId.value = workId;
  f.submit();
}

window.onload = function init() {
  setImage(idx);
  loadTip();
}