// Bildtausch
// Button anlegen
function button(imgPath_out, imgPath_over) {
	this.over	= new Image()
	this.out	= new Image()
	this.over.src	= imgPath_over
	this.out.src	= imgPath_out
}

// Vorausladen der Bilder
var	picture	= new Array()
function preload() {
	picture["logo"]	= new button("/objects/logo.gif", "/objects/logo-over.gif")
//	picture["top"]	= new button("/objects/top.gif", "/objects/top-over.gif")
	picture["t-vb"]	= new button("/objects/t-vb-out.jpg", "/objects/t-vb-over.jpg")
	picture["t-silke"]	= new button("/objects/t-silke-out.jpg", "/objects/t-silke-over.jpg")
	picture["t-micha"]	= new button("/objects/t-micha-out.jpg", "/objects/t-micha-over.jpg")
	picture["t-frauke"]	= new button("/objects/t-frauke-out.jpg", "/objects/t-frauke-over.jpg")
}
preload();

// CSS-Hintergrundbild wechseln
function changeBgImg(Id,Event) {
	if (document.getElementById) {
    	Element = document.getElementById(Id);
		if (Event == 'over') {
        	Element.style.backgroundImage = 'url(' + picture[Id].over.src + ')';
		}
		if (Event == 'out') {
        	Element.style.backgroundImage = 'url(' + picture[Id].out.src + ')';
		}
    }
}

// img-Bild tauschen
function changeImg(Id,Event) {
	if (Event == 'over') {
		document.images[Id].src	= picture[Id].over.src
	}
	if (Event == 'out') {
		document.images[Id].src	= picture[Id].out.src
	}
}

// switch styles
// http://www.alistapart.com/stories/alternate/

function setActiveStyleSheet(title) {
  var i, a, main;
  for (i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if (a.getAttribute("rel") &&
        a.getAttribute("rel").indexOf("style") != -1 &&
        a.getAttribute("title")) {
      a.disabled = true;
      if(a.getAttribute("title") == title) a.disabled = false;
    }
  }
}

function getActiveStyleSheet() {
  var i, a;
  for (i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if (a.getAttribute("rel") &&
        a.getAttribute("rel").indexOf("style") != -1 &&
        a.getAttribute("title") &&
        !a.disabled
        ) return a.getAttribute("title");
  }
  return null;
}

function getPreferredStyleSheet() {
  var i, a;
  for (i=0; (a = document.getElementsByTagName("link")[i]); i++) {
    if (a.getAttribute("rel") &&
        a.getAttribute("rel").indexOf("style") != -1 &&
        a.getAttribute("rel").indexOf("alt") == -1 &&
        a.getAttribute("title")
        ) return a.getAttribute("title");
  }
  return null;
}

function createCookie(name,value,days) {
  if (days) {
    var date = new Date();
    date.setTime(date.getTime()+(days*24*60*60*1000));
    var expires = "; expires="+date.toGMTString();
  }
  else expires = "";
  document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');
  for(var i=0;i < ca.length;i++) {
    var c = ca[i];
    while (c.charAt(0)==' ') c = c.substring(1,c.length);
    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  }
  return null;
}

window.onload = function(e) {
  var cookie = readCookie("style");
  var title = cookie ? cookie : getPreferredStyleSheet();
  setActiveStyleSheet(title);
}

window.onunload = function(e) {
  var title = getActiveStyleSheet();
  createCookie("style", title, 365);
}

var cookie = readCookie("style");
var title = cookie ? cookie : getPreferredStyleSheet();
setActiveStyleSheet(title);