function close_layer(layer_name) {
	YAHOO.util.Dom.setStyle(layer_name,'visibility','hidden');
}
function show_layer(layer_name) {
	YAHOO.util.Dom.setStyle(layer_name,'visibility','visible');
}
function switch_layer(layer_name) {
	current_visibility = YAHOO.util.Dom.getStyle(layer_name,'visibility');
	if (current_visibility == 'visible'){
		YAHOO.util.Dom.setStyle(layer_name,'visibility','hidden');
	} else {
		YAHOO.util.Dom.setStyle(layer_name,'visibility','visible');
	}
}


function display_layer_block(layer_name) {
	YAHOO.util.Dom.setStyle(layer_name,'display','block');
}
function display_layer_none(layer_name) {
	YAHOO.util.Dom.setStyle(layer_name,'display','none');
}
function switch_display_layer(layer_name) {
	current_display = YAHOO.util.Dom.getStyle(layer_name,'display');
	if (current_display == 'block'){
		YAHOO.util.Dom.setStyle(layer_name,'display','none');
	} else {
		YAHOO.util.Dom.setStyle(layer_name,'display','block');
	}
}