var plus = new Image;
plus.src = "/images/plus.gif";
var minus = new Image;
minus.src = "/images/minus.gif";

function show(id) {
	var obj = document.getElementById(id);
	var obj_img = document.getElementById(id + "_plus");
	if (obj.style.display == "none") {
		obj.style.display = "block";
		obj_img.src = minus.src;
		obj_img.alt = "скрыть";
	}
	else {
		obj.style.display = "none";
		obj_img.src = plus.src;
		obj_img.alt = "показать";
	}
	return false;
}