var old;
var memold;
var subold;

if(document.layers)
{
  window.captureEvents(Event.MOUSEDOWN);
  window.onmousedown=do_out;
}else{
  document.onmouseup=do_out;
}

function show_layer(x)
{
  if(document.layers)
  document.layers[x].visibility="show";
else
  document.all[x].style.visibility="visible";
}

function hide_layer(x)
{
  if(document.layers)
    document.layers[x].visibility="hide";
else
  document.all[x].style.visibility="hidden";
}

function do_menu(x)
{
  if(!old)
    old=memold;
  if(old!=x)
  {
    show_layer(x);

    old=x;
  }else
    old="";
}

function do_check(x)
{
  if(!old)
    old=memold;
  if(old && old!=x)
  {
    hide_layer(old);
	show_layer(x);
	old=x;
    memold=x;
  }
  do_submenu();
}

function do_out()
{
	if(old)
      hide_layer(old);
    hide_layers();
	memold=old;
    old="";
	do_submenu();
}

function do_submenu(x)
{
  if(subold)
  {
    hide_layer(subold);
    subold="";
  }
  if(x)
  {
    show_layer(x);
    subold=x;
  }
}