function showHideSubMenu(sMenuId)
{
    var oMenu = document.getElementById(sMenuId);

    if ( oMenu.style.visibility == "visible" )
    {
        oMenu.style.visibility = "hidden";
        oMenu.style.display = "none";
    } 
    else 
    {
        oMenu.style.visibility = "visible";
        oMenu.style.display = "block";
    }

}