//scrolling div

var pages = [];
var currentpage = [];

var scrollAmount=15;
var delay=50; //.5 sec
var timer;
var scrolldiv='content_tentoonstelling';

function use(id) {
	return(document.getElementById(id));
}

function move_left() {
	scrollmove(-scrollAmount);
	timer=window.setTimeout('move_left()', delay);
}

function move_right() {
	scrollmove(scrollAmount);
	timer=window.setTimeout('move_right()', delay);
}

function stop_move() {
	clearInterval(timer);
}

function scrollmove(moveByAmount) {
	var scrollLinks=use(scrolldiv).scrollLeft;
	scrollLinks=scrollLinks+moveByAmount;

	if (scrollLinks<0)
		scrollLinks=0;
	
	use(scrolldiv).scrollLeft=scrollLinks;
}

function next_page(level) {
	var x = currentpage[level]+1;

	if(x > pages[level]) {
		x = 1;
	}
	
	use('menu_'+level+'_layer_' + currentpage[level]).style.display = 'none';
	use('menu_'+level+'_layer_' + x).style.display = 'block';

	currentpage[level] = x;
}

function previous_page(level) {
	var x = currentpage[level]-1;

	if(x < 1) {
		x = pages[level];
	}

	use('menu_'+level+'_layer_' + currentpage[level]).style.display = 'none';
	use('menu_'+level+'_layer_' + x).style.display = 'block';

	currentpage[level] = x;
}

function show(level) {
	for (i=1;i<=pages[level];i++) {
		use('menu_' + level + '_layer_' + i).style.display = 'none';
	}

	use('menu_' + level + '_layer_' + currentpage[level]).style.display = 'none';
	use('menu_' + level + '_layer_' + currentpage[level]).style.display = 'block';
}