/* general variables */
var galleryId = 'gallery'; /* change this to the ID of the gallery list */
var gallery; /* this will be the object reference to the list later on */
var galleryImages; /* array that will hold all child elements of the list */
var currentImage; /* keeps track of which image should currently be showing */
var previousImage;
var preInitTimer;
preInit();

function preInit() {
	if ((document.getElementById)&&(gallery=document.getElementById(galleryId))) {
		gallery.style.visibility = "hidden";
		if (typeof preInitTimer != 'undefined') clearTimeout(preInitTimer);
	} else {
		preInitTimer = setTimeout("preInit()",2);
	}
}

function fader(imageNumber,opacity) {
	var obj=galleryImages[imageNumber];
	if (obj.style) {
		if (obj.style.MozOpacity!=null) {  
			/* Mozilla's pre-CSS3 proprietary rule */
			obj.style.MozOpacity = (opacity/100) - .001;
		} else if (obj.style.opacity!=null) {
			/* CSS3 compatible */
			obj.style.opacity = (opacity/100) - .001;
		} else if (obj.style.filter!=null) {
			/* IE's proprietary filter */
			obj.style.filter = "alpha(opacity="+opacity+")";
		}
	}
}

function fadeInit(speed) {
	if (document.getElementById) {
		preInit(); /* shouldn't be necessary, but IE can sometimes get ahead of itself and trigger fadeInit first */
		galleryImages = new Array;
		var node = gallery.firstChild;
		/* instead of using childNodes (which also gets empty nodes and messes up the script later)
		we do it the old-fashioned way and loop through the first child and its siblings */
		while (node) {
			if (node.nodeType==1) {
				galleryImages.push(node);
			}
			node = node.nextSibling;
		}
		for(i=0;i<galleryImages.length;i++) {
			/* loop through all these child nodes and set up their styles */
			galleryImages[i].style.position='absolute';
			galleryImages[i].style.top=0;
			galleryImages[i].style.zIndex=0;
			/* set their opacity to transparent */
			fader(i,0);
		}
		/* make the list visible again */
		gallery.style.visibility = 'visible';
		/* initialise a few parameters to get the cycle going */
		currentImage=0;
		previousImage=galleryImages.length-1;
		opacity=100;
		fader(currentImage,100);
		/* start the whole crossfade process after a second's pause */
		window.setTimeout("crossfade(100,"+speed+")", 1000);
	}
}

function crossfade(opacity, speed) {
	if (opacity < 100) {
		fader(currentImage,opacity);
		opacity += 10;
		window.setTimeout("crossfade("+opacity+","+speed+")", 30);
	} else {
		fader(previousImage,0);
			previousImage=currentImage;
			currentImage+=1;
			if (currentImage>=galleryImages.length) {
				currentImage=0;
			}
			galleryImages[previousImage].style.zIndex = 0;
			galleryImages[currentImage].style.zIndex = 100;
			opacity=0;
			window.setTimeout("crossfade("+opacity+","+speed+")", speed);
		}
		
}

/* initialise fader by hiding image object first */
function start_crossfade(speed){
	addEvent(window,'load',fadeInit(speed));
}

/* addEvent handler for IE and other browsers */
function addEvent(elm, evType, fn, useCapture){
 if (elm.addEventListener){
   elm.addEventListener(evType, fn, useCapture);
   return true;
 } else if (elm.attachEvent){
   var r = elm.attachEvent("on"+evType, fn);
   return r;
 }
}