function layer_hide (layername) {
	if(document.layers) { layer = document.layers[layername]; layer.visibility = "hidden"; }
	if(document.all) { layer = document.all[layername]; layer.style.visibility = "hidden"; }
	if(!document.all && document.getElementById){ layer = document.getElementById(layername); layer.style.visibility = "hidden"; }
}
function layer_show (layername) {
	if(document.layers) { layer = document.layers[layername]; layer.visibility = "visible"; }
	if(document.all) { layer = document.all[layername]; layer.style.visibility = "visible"; }
	if(!document.all && document.getElementById){ layer = document.getElementById(layername); layer.style.visibility = "visible"; }
}