function button_over(button_key, index) { 
	var button, img;
	button = buttons[button_key];
	img = getElem("id", button["image"]+"_"+index);
	img.src = eval(button_key + "_over.src");
}

function button_out(button_key, index) {
	var button, group_id, img;
	button = buttons[button_key];
    group_id = button["group_id"];
    img = getElem("id", button["image"]+"_"+index);
	if (active_button_key[group_id] != button_key) {
		img.src = eval(button_key + "_normal.src");
	}
}

function button_activate(button_key, index) { 
	var button, group_id, img, last_img, img_name;
	button = buttons[button_key];
    group_id = button["group_id"];
    img = getElem("id", button["image"]+"_"+index);
	if (active_button_key[group_id] != button_key) {
		if (active_button_key[group_id] != undefined) {
			img_name = buttons[active_button_key[group_id]]["image"];
			last_img = getElem("id", img_name+"_"+active_button_index[group_id]);
			last_img.src = eval(active_button_key[group_id] + "_normal.src");
		}
 		img.src = eval(button_key + "_over.src");
	}
	active_button_key[group_id] = button_key;
	active_button_index[group_id] = index;	
}

function remember_activated_button(button_key) {
    var button, group_id;
    button = buttons[button_key];
    group_id = button["group_id"];
	active_button_key[group_id] = button_key;
	active_button_index[group_id] = 0;
}