var delay = 100;
var timer;
var opened_menu_id = "";

function open_menu(m_id)
{
 if (opened_menu_id != "")
  close_menu(opened_menu_id);

 document.getElementById(m_id).style.display = "block";
 opened_menu_id = m_id;
}

function close_menu()
{
 document.getElementById(opened_menu_id).style.display = "none";
}

function close_timer()
{
 timer = setTimeout(close_menu, delay);
}

function reset_timer()
{
 if (timer)
 {
  clearTimeout(timer);
  timer = false;
 }
}