function getImgSrc(src,index)
{
	var position = src.indexOf("_");
	var index_img = src.substring(position + 1, position + 2);
	//var new_index_img = parseInt(index_img) + index;
	var ret = src.substring(0, position + 1) + index + src.substring(position + 2);
	return ret;
}
function imgPrev(link)
{
	var dl = link.parentNode;
	while(dl.nodeName != 'DL')
	{
		dl = dl.parentNode;
	}
	var src_img = dl.getElementsByTagName('img')[0].getAttribute('src');
	var id_img = dl.getElementsByTagName('img')[0].getAttribute('id');
	var position = src_img.indexOf("_");
	var index_img = src_img.substring(position + 1, position + 2);
	var arr_ids = id_img.split('_');
			
	for(var i = 2; i < arr_ids.length; i++)
	{
		if(index_img == arr_ids[i])
		{
			if(i > 2)
			{
				dl.getElementsByTagName('img')[0].setAttribute('src', getImgSrc(src_img, arr_ids[i - 1]));
			}
			else
			{
				// last img
				dl.getElementsByTagName('img')[0].setAttribute('src', getImgSrc(src_img, arr_ids[arr_ids.length - 1]));
			}
		}
	}
}
function imgSuiv(link)
{
	var dl = link.parentNode;
	while(dl.nodeName != 'DL')
	{
		dl = dl.parentNode;
	}
	var src_img = dl.getElementsByTagName('img')[0].getAttribute('src');
	var id_img = dl.getElementsByTagName('img')[0].getAttribute('id');
	var position = src_img.indexOf("_");
	var index_img = src_img.substring(position + 1, position + 2);
	var arr_ids = id_img.split('_');
	
	for(var i = 2; i < arr_ids.length; i++)
	{
		if(index_img == arr_ids[i])
		{
			if(i < arr_ids.length - 1)
			{
				dl.getElementsByTagName('img')[0].setAttribute('src', getImgSrc(src_img, arr_ids[i + 1]));
			}
			else
			{
				// first img
				dl.getElementsByTagName('img')[0].setAttribute('src', getImgSrc(src_img, arr_ids[2]));
			}
		}
	}
}