var state = 'hidden';

function showhide(layer_ref) {

	if (state == 'visible')
	{
		state = 'hidden';
	} else {
		state = 'visible';
	}

	if (document.all)
	{ //IS IE 4 or 5 (or 6 beta)
		eval( "document.all." + layer_ref + ".style.visibility = state");
	}
	if (document.layers)
	{ //IS NETSCAPE 4 or below
		document.layers[layer_ref].visibility = state;
	}
	if (document.getElementById && !document.all)
	{
		maxwell_smart = document.getElementById(layer_ref);
		maxwell_smart.style.visibility = state;
	}
}