var menuDisplayed = '';
var timer;

function showMenu(menu)
{
	if(timer)
		clearTimeout(timer);
	hideMenu(menuDisplayed);
	document.getElementById(menu).style.visibility = 'visible';
	menuDisplayed = menu;
	
}
function hideMenuDelayed(menu)
{
	timer = setTimeout("hideMenu(menuDisplayed)", 500);
}

function hideMenu(menu)
{
	clearTimeout(timer);
	if(menuDisplayed!='')
		document.getElementById(menu).style.visibility = 'hidden';
	menuDisplayed = '';
	
}