var current_gallery_item = 0;
var gallery_images = new Array();
var gallery_captions = new Array();
			
function previousImage() {
	current_gallery_item --;
	if (current_gallery_item < 0) { current_gallery_item = gallery_images.length - 1; }
	refresh();
}

function nextImage() {
	current_gallery_item ++;
	if (current_gallery_item == gallery_images.length) { current_gallery_item = 0; }
	refresh();
}

function gotoImage(i) {
	if (i >= 0 && i < gallery_images.length) {
		// value is valid
	} else {
		// value is invalid, default to 0
		i = 0;
	} 
	
	current_gallery_item = i;
	refresh();
}

function refresh() {
	// check if a gallery exists
	if (gallery_images.length > 0) {
		// render the gallery elements
		document.getElementById('gallery_image').innerHTML = '<img src="'+ relative_path +'user_files/gallery_images/'+ gallery_images[current_gallery_item] +'" />';
		document.getElementById('gallery_caption').innerHTML = gallery_captions[current_gallery_item];
		
		// update the list of pages
		var page_links = '';
		for (n=1; n <= gallery_images.length; n++) {
			// check if this is the current page
			if (current_gallery_item == n-1) { 
				page_links = page_links + ' ' + '<a href="#" onclick="javascript:gotoImage('+ (n-1) +')" id="current">' + n + '</a>';
			} else {
				page_links = page_links + ' ' + '<a href="#" onclick="javascript:gotoImage('+ (n-1) +')">' + n + '</a>';
			}
		}
		
		document.getElementById('gallery_pages').innerHTML = page_links;		
	}
}