var strCurrentMenu = "";

function showSubMenu(strWhich) {
  if ((strWhich != strCurrentMenu) && strCurrentMenu != "") {
    document.getElementById("subMenu-"+strCurrentMenu).style.display = "none";
    }
  strCurrentMenu = strWhich;
  document.getElementById("subMenu-"+strWhich).style.display = "block";
}
function hideSubMenu(strWhich) {
  if (strWhich == "") {
    strWhich = strCurrentMenu;
    }
  if (strWhich != "") {  
    document.getElementById("subMenu-"+strWhich).style.display = "none";
  }
  strCurrentMenu = "";      
}