function el(Id) { if(document.getElementById(Id)) return document.getElementById(Id); else return false; }
function elStyle(Id) { if(document.getElementById(Id)) return document.getElementById(Id).style; else return false; }
function elHide(Id) { if(document.getElementById(Id)) document.getElementById(Id).style.display='none'; }
function elShow(Id) { if(document.getElementById(Id)) document.getElementById(Id).style.display='block'; }
function isEl(Id) { if(document.getElementById(Id)) return true; else return false; }
function bgSwap(Id,Src) { elStyle(Id).backgroundImage = "url('"+Src+"')"; }

var menuLVisible = '';
var menuLSubVisible = '';
var menuLSub2Visible = '';

function menuLShow(Id, IdSub, IdSub2)
{
  if( menuLVisible==Id )
  {
    if( menuLSubVisible==IdSub )
    {
      if( menuLSub2Visible==IdSub2 )
      {
      }
      else
      {
        elHide(menuLSub2Visible);
        elShow(IdSub2);
      }
    }
    else
    {
      elHide(menuLSubVisible);  elHide(menuLSub2Visible);
      elShow(IdSub); elShow(IdSub2);
    }
  }
  else
  {
    elHide(menuLVisible); elHide(menuLSubVisible);  elHide(menuLSub2Visible);
    elShow(Id); elShow(IdSub);  elShow(IdSub2);
  }
  menuLVisible = Id;
  menuLSubVisible = IdSub;
  menuLSub2Visible = IdSub2;
}