var last_img_id = "t1";

function ShowImg(img_id, medium_src, caption_id) {
	img = document.getElementById("current_img");
	img.src = medium_src;
	Highlight(img_id);
	ShowImgText(caption_id);
	last_img_id = img_id;
}

function ShowImgText(caption_id){
	for (var i = 1; i <= img_count; i++) {
		var id = "c" + i;
		var caption_div = document.getElementById(id);
		if(caption_div != null) caption_div.style.display = (id == caption_id) ? "block" : "none";
	}
}

function Highlight(img_id) {
	if (img_id == null) img_id = last_img_id;
	UnHighlight();
	var img = document.getElementById(img_id);
	if(img != null) {
		img.className = "imgbox_on";
	}
	img = document.getElementById("current_img");
	if(img != null) {
		img.parentNode.className = "imgbox_on";
	}
}

function UnHighlight() {
	var thumbnails = document.getElementById("thumbnails");
	if (thumbnails != null) {
		var divs = thumbnails.getElementsByTagName("td");
		for (i = 0; i < divs.length; i++) {
			divs[i].className = "imgbox_off";
		}
		var divs = thumbnails.getElementsByTagName("div");
		for (i = 0; i < divs.length; i++) {
			divs[i].className = "imgbox_off";
		}
	}
	img = document.getElementById("current_img");
	if(img != null) {
		img.parentNode.className = "imgbox_off";
	}
}