function change_class(div_id, css_class)
{
	document.getElementById(div_id).className = css_class;
}

function get_height(){
	var d= document.documentElement;
	var b= document.body;
	var who= d.offsetHeight? d: b ;
	return Math.max(who.scrollHeight,who.offsetHeight);
}

function set_height(div_id, height_type)
{
	var body_height = get_height()+"px";
	
	if(height_type == "max"){set_height = body_height;}
	else if(height_type == "min"){set_height = "0px";}
	
	document.getElementById(div_id).style.height = set_height;
}

function load_caption()
{
	document.getElementById("viewer_captions").innerHTML = caption_array[position];
}

function show_viewer(rank)
{
	position = rank;

	if(open == false)
	{
		change_class("overlay", "show_overlay");
		set_height("overlay", "max");
		url = link+rank;
		ajax_page_to_div(index, url, "overlay");
		change_class("viewer_loader", "show_loader");
		load_caption();
		
		open = true;
	}
	else
	{
		change_class("overlay", "show_overlay");
		url = images_array[position];
		main_viewer_image(url, position);
	}
	
	index++;
}

function main_image(url, rank)
{
	position = rank; 
	document.main_img.src = url;
}

function main_viewer_image(url, rank)
{
	if(rank == position){return false;}
	position = rank; 
	change_class("viewer_loader", "show_loader");
	document.viewer_main.src = url;
	load_caption();
}

function next()
{
	//alert(position);
	if(img_total == 1){return false;}
	else if(position == last){rank = first;}
	else{rank = position + 1;}
	url = images_array[rank];
	
	main_viewer_image(url, rank);	
}

function previous()
{
	//alert(position);
	if(img_total == 1){return false;}
	else if(position == first){rank = last;}
	else{rank = position - 1;}
	url = images_array[rank];
	
	main_viewer_image(url, rank);	
}

function close_viewer()
{
	change_class("overlay", "hide_overlay");
}