var current_id = false;
function setvisibility(layer_ref, state) {
	if (document.layers) { //IS NETSCAPE 4 or below
		if(document.layers[layer_ref]) document.layers[layer_ref].display = state;
	} else if (document.getElementById) {
		hza = document.getElementById(layer_ref);
		hza.style.display = state;
	}
}

function hide_show(obj, d) {
	if(current_id) {
		setvisibility(current_id, 'none');
		obj.title = 'Show';
	}
	if(current_id != d) {
		setvisibility(d, 'block');
		current_id = d;
		obj.title = 'Hide';
	} else current_id = false;
}