var currentMenuButton = null;
var currentMenu = null;
var currentMenuItem = null;
var itemTimeout = null;
var menuItemTimeout = null;
var timer = null;

var itemDivId = {
   'hall' : 'tnNavHall',
   'ext' : 'tnNavExt'
   };
var menuId = {
   'hall' : 'tnNavHallMenu',
   'ext' : 'tnNavExtMenu'
   };
var menuLeft = {
   'hall' : 420,
   'ext' : 580
   };

function topnavItemOn(section) {
   if (currentMenu != document.getElementById(menuId[section])) {
      
      // turn off current menu
      topnavCurrentItemOff();
      
      // if button is already on, it's the default - set flag to remember not to turn off
      currentMenuButton = document.getElementById(itemDivId[section]).firstChild.firstChild;
      
      // position menu horizontally and adjust if it's too wide
      currentMenu = document.getElementById(menuId[section]);
      
      // show new menu (set top position to in-screen value)
      currentMenu.style.visibility = 'visible';
      
      // add click-to-hide-menu handler to document
      document.onmouseup = topnavCurrentItemOff;
   }
}

function topnavItemOff(section) {
	timer = setTimeout('topnavCurrentItemOff()', 1500);
}

function killDelay() {
  clearTimeout(timer);
}

function topnavCurrentItemOff() {
   if (currentMenu != null) {
      
      currentMenuButton = null;
      
      // hide current menu
      currentMenu.style.visibility = 'hidden';
      currentMenu = null;
      
      // remove click-to-hide-menu handler
      document.onmouseup = function() {}
   }
}