// containers for links and pictures
var arr_links = new Array();
var arr_images = new Array();
var arr_title1 = new Array();
var arr_title2 = new Array();
var visits = 0;

// Cookie Maintenance 
// Cookie-Existenz-Test - 101214cr 
function extractCookieValue(val) {
  if ((endOfCookie = document.cookie.indexOf(";", val)) == -1) {
     endOfCookie = document.cookie.length;
  }
  return unescape(document.cookie.substring(val,endOfCookie));
}
	
// Cookie-Lesefunktion - 101214cr 
function ReadCookie(cookiename) {
  var numOfCookies = document.cookie.length;
  var nameOfCookie = cookiename + "=";
  var cookieLen = nameOfCookie.length;
  var x = 0;
  while (x <= numOfCookies) {
        var y = (x + cookieLen);
        if (document.cookie.substring(x, y) == nameOfCookie)
           return (extractCookieValue(y));
           x = document.cookie.indexOf(" ", x) + 1;
           if (x == 0){
              break;
           }
  }
  return (null);
}

// Cookie-Schreibfunktion - 101214cr 	
function createCookie(name, value) {
	document.cookie = name + "=" + value + ";"
}

// Eigentliche Referenz-Funktion - mkdesign
function ref_init() {
	userCookie = ReadCookie("_visitSite");
	if (userCookie == null)
		visits = 0;
	else
		visits = parseInt(userCookie) + 3;
		createCookie("_visitSite", visits);
  // read images and links
  var max_number = read_data();
  
  // update images and links for given offset
  show_data(visits % max_number);
}


// update images and links
function show_data(visits)
{
  var ul_tag = document.getElementById('references');
  var li_tags = ul_tag.getElementsByTagName('li');
  var max_number = li_tags.length;

  // loop: iteratation for each image
  for(i=0; i<max_number; i++)
  {
    var source_id = (i + visits) % max_number;
    
    // link
    var href = arr_links[source_id];
    var a_tag = li_tags[i].getElementsByTagName('a')[0];
    a_tag.setAttribute('href', href);
    var title1 = arr_title1[source_id];
    a_tag.setAttribute('title', title1);
    
    // image
    var src = arr_images[source_id];
    var img_tag = a_tag.getElementsByTagName('img')[0];
    img_tag.setAttribute('src', src);
    var title2 = arr_title2[source_id];
    img_tag.setAttribute('title', title2);
  }
}


// read images and links
function read_data()
{
  var ul_tag = document.getElementById('references');
  var li_tags = ul_tag.getElementsByTagName('li');
  var max_number = li_tags.length;
  
  // loop: iteratation for each image
  for(i=0; i<max_number; i++)
  {
    // link
    var a_tag = li_tags[i].getElementsByTagName('a')[0];
    arr_links[i] = a_tag.getAttribute('href');
    arr_title1[i] = a_tag.getAttribute('title');
    
    // image
    var img_tag = a_tag.getElementsByTagName('img')[0];
    arr_images[i] = img_tag.getAttribute('src');
    arr_title2[i] = img_tag.getAttribute('title');
  }  
  
  return max_number;
}