var loadingImage = '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 (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else {
		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 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;

		objLightbox.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - imgPreload.height) / 2) + 'px');
		objLightbox.style.left = (((arrayPageSize[0] - 40 - imgPreload.width) / 2) + 'px');

		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.onmouseover = 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 = '90';
 	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 = '150';
		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 = '100';	
	objBody.insertBefore(objLightbox, objOverlay.nextSibling);
	
	var objLink = document.createElement("a");
	objLink.setAttribute('href','#');
	objLink.onclick = function () {hideLightbox(); return false;}
	objLightbox.appendChild(objLink);
	
	var objImage = document.createElement("img");
	objImage.setAttribute('id','lightboxImage');
	objLink.appendChild(objImage);
}

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

}


addLoadEvent(initLightbox);	// run initLightbox onLoad