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!=x){
    hide_layer(old);
    show_layer(x);
    old=x;
  }
  do_submenu();
}

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

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