function hideIt(object)
{
	object.style.visibility="hidden";
}

function showIt(object)
{
	if (object !== null)
	{
		object.style.visibility="visible";
	}
}


function hideActive()
{
	if (activeMenu !== null)
	{
		hideIt(activeMenu);
		activeMenu = null;
	}
}

function showMenu(M)
{
	hideActive();
	activeMenu = document.getElementById(M);
	showIt(activeMenu);
}