var loadingImage = 'index-dateien/loading.gif';

function getPageScroll(){
        var yScroll;
        if (self.pageYOffset) {
                yScroll = self.pageYOffset;
        } else if (document.documentElement && document.documentElement.scrollTop){         // Explorer 6 Strict
                yScroll = document.documentElement.scrollTop;
        } else if (document.body) {// all other Explorers
                yScroll = document.body.scrollTop;
        }
        arrayPageScroll = new Array('',yScroll)
        return arrayPageScroll;
}

function getPageSize(){
        var xScroll, yScroll;
        if (window.innerHeight && window.scrollMaxY) {
                xScroll = document.body.scrollWidth;
                yScroll = window.innerHeight + window.scrollMaxY;
        } else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
                xScroll = document.body.scrollWidth;
                yScroll = document.body.scrollHeight;
        } else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
                xScroll = document.body.offsetWidth;
                yScroll = document.body.offsetHeight;
        }
        var windowWidth, windowHeight;
        if (self.innerHeight) {        // all except Explorer
                windowWidth = self.innerWidth;
                windowHeight = self.innerHeight;
        } else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
                windowWidth = document.documentElement.clientWidth;
                windowHeight = document.documentElement.clientHeight;
        } else if (document.body) { // other Explorers
                windowWidth = document.body.clientWidth;
                windowHeight = document.body.clientHeight;
        }
        if(yScroll < windowHeight){
                pageHeight = windowHeight;
        } else {
                pageHeight = yScroll;
        }
        if(xScroll < windowWidth){
                pageWidth = windowWidth;
        } else {
                pageWidth = xScroll;
        }
        arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight)
        return arrayPageSize;
}

function pause(numberMillis) {
        var now = new Date();
        var exitTime = now.getTime() + numberMillis;
        while (true) {
                now = new Date();
                if (now.getTime() > exitTime)
                        return;
        }
}

function showLightbox(objLink) {
        var objOverlay = document.getElementById('overlay');
        var objLightbox = document.getElementById('lightbox');
        var objCaption = document.getElementById('lightboxCaption');
        var objImage = document.getElementById('lightboxImage');
        var objLoadingImage = document.getElementById('loadingImage');
        var arrayPageSize = getPageSize();
        var arrayPageScroll = getPageScroll();
        if (objLoadingImage) {
                objLoadingImage.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - objLoadingImage.height) / 2) + 'px');
                objLoadingImage.style.left = (((arrayPageSize[0] - 40 - objLoadingImage.width) / 2) + 'px');
        }
        objOverlay.style.height = (arrayPageSize[1] + 'px');
        objOverlay.style.display = 'block';
        imgPreload = new Image();

        imgPreload.onload=function(){
                objImage.src = objLink.href;
                var lightboxTop = arrayPageScroll[1] + ((arrayPageSize[3] - 35 - imgPreload.height) / 2);
                var lightboxLeft = ((arrayPageSize[0] - 40 - imgPreload.width) / 2);
                objLightbox.style.top = (lightboxTop < 0) ? "0px" : lightboxTop + "px";
                objLightbox.style.left = (lightboxLeft < 0) ? "0px" : lightboxLeft + "px";
                if(objLink.getAttribute('title')){
                        objCaption.style.display = 'block';
                        objCaption.style.width = imgPreload.width + 'px';
                        objCaption.innerHTML = objLink.getAttribute('title');
                } else {
                        objCaption.style.display = 'none';
                }
                if (navigator.appVersion.indexOf("MSIE")!=-1){
                        pause(250);
                }
                objLightbox.style.display = 'block';
                return false;
        }
        imgPreload.src = objLink.href;
}

function hideLightbox() {
        objOverlay = document.getElementById('overlay');
        objLightbox = document.getElementById('lightbox');
        objOverlay.style.display = 'none';
        objLightbox.style.display = 'none';
}

function initLightbox()  {
        if (!document.getElementsByTagName){ return; }
        var anchors = document.getElementsByTagName("a");
        for (var i=0; i<anchors.length; i++){
                var anchor = anchors[i];
                if (anchor.getAttribute("href") && (anchor.getAttribute("rel") == "lightbox")){
                        anchor.onclick = function () {showLightbox(this); return false;}
                }
        }
        var objBody = document.getElementsByTagName("body").item(0);
        var objOverlay = document.createElement("div");
        objOverlay.setAttribute('id','overlay');
        objOverlay.style.display = 'none';
        objOverlay.style.position = 'absolute';
        objOverlay.style.top = '0';
        objOverlay.style.left = '0';
        objOverlay.style.zIndex = '1000';
        objOverlay.style.width = '100%';
        objBody.insertBefore(objOverlay, objBody.firstChild);
        var arrayPageSize = getPageSize();
        var arrayPageScroll = getPageScroll();
        var imgPreloader = new Image();
        imgPreloader.onload=function(){
                var objLoadingImageLink = document.createElement("a");
                objLoadingImageLink.setAttribute('href','#');
                objLoadingImageLink.onclick = function () {hideLightbox(); return false;}
                objOverlay.appendChild(objLoadingImageLink);
                var objLoadingImage = document.createElement("img");
                objLoadingImage.src = loadingImage;
                objLoadingImage.setAttribute('id','loadingImage');
                objLoadingImage.style.position = 'absolute';
                objLoadingImage.style.zIndex = '1002';
                objLoadingImageLink.appendChild(objLoadingImage);
                imgPreloader.onload=function(){};
                return false;
        }
        imgPreloader.src = loadingImage;
        var objLightbox = document.createElement("div");
        objLightbox.setAttribute('id','lightbox');
        objLightbox.style.display = 'none';
        objLightbox.style.position = 'absolute';
        objLightbox.style.zIndex = '1001';
        objBody.insertBefore(objLightbox, objOverlay.nextSibling);
        var objLink = document.createElement("a");
        objLink.setAttribute('href','#');
        objLink.setAttribute('title','Klicke um zu schließen!');
        objLink.onclick = function () {hideLightbox(); return false;}
        objLightbox.appendChild(objLink);
        var objImage = document.createElement("img");
        objImage.setAttribute('id','lightboxImage');
        objLink.appendChild(objImage);
        var objCaption = document.createElement("div");
        objCaption.setAttribute('id','lightboxCaption');
        objCaption.style.display = 'none';
        objLightbox.appendChild(objCaption);
}

function addLoadEvent(func) {
        var oldonload = window.onload;
        if (typeof window.onload != 'function'){
            window.onload = func;
        } else {
                window.onload = function(){
                oldonload();
                func();
                }
        }
}

addLoadEvent(initLightbox);