function showMenu(id)
{
	hideAllMenus();
	var element = document.getElementById(id);
	if (element)
	{
		element.style.display = 'block';
	}
}
function hideAllMenus()
{
	hideMenu('submenu1');
	hideMenu('submenu2');
	hideMenu('submenu3');
	hideMenu('submenu4');
}
function hideMenu(id)
{
	var element = document.getElementById(id);
	if (element)
	{
		element.style.display = 'none';
	}
}