/* main menu */
function showSubmenu( id ) {
	var n = id.toString();
	var obj = get( 'menu_'+n );
	obj.src = '/graph/menu_over_'+n+'.gif';
}

function hideSubmenu( id ) {
	var n = id.toString();	
	var obj = get( 'menu_'+n );
	obj.src = '/graph/menu_'+n+'.gif';
}

/* left menu */
document.openedSubMenu = new Array();
function toggleSubMenu( id ) {
	hideAllSubMenu();
	var obj = get( id );
	if( obj != undefined ) {
		var vis = obj.style.display;
		if( vis == 'block' ) {
			obj.style.display = 'none';
		} else {
			obj.style.display = 'block';
			document.openedSubMenu.push( id );
		}
	}
}

function hideAllSubMenu() {
	while( document.openedSubMenu.length > 0 ) {
		var id = document.openedSubMenu.pop();
		hide( id );
	}
}