var scrollAmount=1;
var scrollSpeed=10;
var scrollIntervalId;

var scrolledLayer;
var scrolledLayerHeight;

var scrollUpDivHeight;
var scrollDownDivHeight;
var thumbsLayerDisplayHeight;


/**
*
*
**/
function init(){
	scrolledLayer=document.getElementById('gallery-2-thumbnails');
	scrolledLayerHeight=parseInt(scrolledLayer.offsetHeight);
	
	//alert(scrolledLayerHeight);
}


/**
*
*
**/
function getScrollingDivMarginTop(divRef){
	if(divRef.style.marginTop.length==0)
		return 20;
		
	return parseInt(divRef.style.marginTop.replace('px',''));
}


/**
*
*
**/
function scrollUp(){
	
	var top=getScrollingDivMarginTop(scrolledLayer);
	
	if(290-top<scrolledLayerHeight)
		scrolledLayer.style.marginTop=parseInt(top-scrollAmount)+'px';
	else
		stopScroll();
		
}


/**
*
*
**/
function scrollDown(){
	
	var top=getScrollingDivMarginTop(scrolledLayer);
	
	if(top<20)
		scrolledLayer.style.marginTop=parseInt(top+scrollAmount)+'px';
	else
		stopScroll();	
}


/**
*
*
**/
function startScrolling(direction){
	
	init();
	
	if(direction=='down'){
		scrollIntervalId=setInterval('scrollDown()',scrollSpeed)
	}	
	else{
		scrollIntervalId=setInterval('scrollUp()',scrollSpeed);	
	}	
}


/**
*
*
**/
function stopScroll(){
	//alert(document.getElementById('gallery-2-thumbnails').offsetHeight);
	clearInterval(scrollIntervalId);
}


/**
*
*
**/
function loadImage(imgSrc){
	document.getElementById('gallery2-enlarged-image').src=imgSrc;
}