var loaded_imgs = new Object();
var imgs = new Array("img1", "img2", "img3", "img4");
for( var i = 0; i < imgs.length; i++)
{
	var obj_name = imgs[i];
	loaded_imgs[obj_name] = new Image();
	loaded_imgs[obj_name].src = "images/" + (i + 1) + "small_on.jpg";
}

function swap_img(img)
{
	if (!img || !document.getElementById)
	{
		return;
	}
	var txt = img.src.substr(-6,2);
	if (txt != "ff")
	{
		return;
	}
	img.src = loaded_imgs[img.id].src;
}

function restore_img(img)
{
	if (!img || !document.getElementById)
	{
		return;
	}
	var txt = img.src.substr(-6,2);
	if (txt != "on")
	{
		return;
	}
	var new_txt = img.src.substr(0,(img.src.length-6));
	img.src = new_txt + "off" + ".jpg";
}

function imgSelection(elem)
{
	if (document.getElementById)
	{
		if (elem)
		{

			// get new image info
			var new_src_ary = elem.src.split("/");
			var new_file_name = new_src_ary[new_src_ary.length - 1];
			var new_num = new_file_name.substr(0,1);
			
			for (var i = 1; i < 5; i++)
			{
				var current_div = document.getElementById("div"+i);
				if (current_div)
				{
					current_div.style.visibility = ((i == new_num) ? "visible" : "hidden");
				}
				var current_img = document.getElementById("img" + i);
				if (current_img)
				{
					current_img.src = "images/" + i + ( (i == new_num) ? "large.jpg" : "small_off.jpg");
				}
			}
		}
	}
}