function show_menu(link) {
	
	document.getElementById( 'menu1' ).style.visibility = 'hidden';
	document.getElementById( 'menu2' ).style.visibility = 'hidden';
	document.getElementById( 'menu3' ).style.visibility = 'hidden';
	document.getElementById( 'menu4' ).style.visibility = 'hidden';
	document.getElementById( 'menu5' ).style.visibility = 'hidden';
	
	document.getElementById( link ).style.visibility = 'visible';
}

function hide_menus() {

	document.getElementById( 'menu1' ).style.visibility = 'hidden';
	document.getElementById( 'menu2' ).style.visibility = 'hidden';
	document.getElementById( 'menu3' ).style.visibility = 'hidden';
	document.getElementById( 'menu4' ).style.visibility = 'hidden';
	document.getElementById( 'menu5' ).style.visibility = 'hidden';
}

function initMenus() {
	
	document.getElementById('top_left').onmouseover = hide_menus;
	document.getElementById('top_right').onmouseover = hide_menus;
	document.getElementById('spacer').onmouseover = hide_menus;
	document.getElementById('middle_right').onmouseover = hide_menus;
	document.getElementById('nav_links').onmouseover = hide_menus;
	document.getElementById('flag_links').onmouseover = hide_menus;
}

window.addOnloadListener(initMenus);