var transition = 15;
var speed = 70;
var currImage = 0;

var imageId = "photoBox";
var image = document.getElementById(imageId);

function initImage() {
	currImage = 1;
	image = document.getElementById(imageId);
	image.src = arrImages[currImage];
	image.alt = arrCaptions[currImage];
	setOpacity(image, 100);
	updateCaption(currImage);
}

function setOpacity(obj, opacity) {
	opacity = (opacity == 100)?99.999:opacity;
	// IE/Win
	obj.style.filter = "alpha(opacity:"+opacity+")";
	// Safari<1.2, Konqueror
	obj.style.KHTMLOpacity = opacity/100;
	// Older Mozilla and Firefox
	obj.style.MozOpacity = opacity/100;
	// Safari 1.2, newer Firefox and Mozilla, CSS3
	obj.style.opacity = opacity/100;
}

function fadeIn(objId,opacity) {
	if (document.getElementById) {
		obj = document.getElementById(objId);
		if (opacity <= 100) {
			setOpacity(obj, opacity);
			opacity += transition;
			window.setTimeout("fadeIn('"+objId+"',"+opacity+")", speed);
		}
	}
}

function fadeOut(objId,opacity) {
	if (document.getElementById) {
		obj = document.getElementById(objId);
		if (opacity > 0 && opacity <= transition)
			opacity = 0;
		if (opacity >= 0) {
			setOpacity(obj, opacity);
			opacity -= transition;
			window.setTimeout("fadeOut('"+objId+"',"+opacity+")", speed);
		}
	}
}

function showImage() { fadeIn(imageId, 1); }
function hideImage() { fadeOut(imageId, 100); }

function nextImage() {
	if (currImage < lastImage)
		currImage += 1;
	else
		currImage = 1;

	fadeOut(imageId, 100);
	image.src = arrImages[currImage];
	image.alt = arrCaptions[currImage];
	fadeIn(imageId, 1);
	updateCaption(currImage);
}

function prevImage() {
	if (currImage == 1)
		currImage = lastImage;
	else
		currImage -= 1;

	fadeOut(imageId, 100);
	image.src = arrImages[currImage];
	image.alt = arrCaptions[currImage];
	fadeIn(imageId, 1);
	updateCaption(currImage);
}

function updateCaption(idx) {
	if (document.getElementById) {
		document.getElementById("captionBox").innerHTML = arrCaptions[idx];
		document.getElementById("photoCredit").innerHTML = arrCredits[idx];
		document.getElementById("photoNumber").innerHTML = currImage + " of " + lastImage;
	}
}

function popBigImage() {
	var winFeatures = "menubar=0,toolbar=0,statusbar=0,personalbar=0,screenX=50,screenY=50,width=500,height=400,resizable=1";
	var w = window.open(arrImages[currImage], "BigPhoto", winFeatures);
	w.focus();
}