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