function showMenu(menu) {

document.getElementById(menu).style.visibility='visible';
}

function hideMenu(menu) {
document.getElementById(menu).style.visibility='hidden';
}

function hideOtherMenus(except) {

for(i = 1;i<=5;i++)
{

if (except != i)
{
document.getElementById('SubMenu' + i).style.visibility = 'hidden';
}
}
}