viewport = {
  getWinWidth: function () {
    this.width = 0;
    if (window.innerWidth) this.width = window.innerWidth - 18;
    else if (document.documentElement && document.documentElement.clientWidth) 
  		this.width = document.documentElement.clientWidth;
    else if (document.body && document.body.clientWidth) 
  		this.width = document.body.clientWidth;
  },
  
  getWinHeight: function () {
    this.height = 0;
    if (window.innerHeight) this.height = window.innerHeight - 18;
  	else if (document.documentElement && document.documentElement.clientHeight) 
  		this.height = document.documentElement.clientHeight;
  	else if (document.body && document.body.clientHeight) 
  		this.height = document.body.clientHeight;
  },
  
  getScrollX: function () {
    this.scrollX = 0;
  	if (typeof window.pageXOffset == "number") this.scrollX = window.pageXOffset;
  	else if (document.documentElement && document.documentElement.scrollLeft)
  		this.scrollX = document.documentElement.scrollLeft;
  	else if (document.body && document.body.scrollLeft) 
  		this.scrollX = document.body.scrollLeft; 
  	else if (window.scrollX) this.scrollX = window.scrollX;
  },
  
  getScrollY: function () {
    this.scrollY = 0;    
    if (typeof window.pageYOffset == "number") this.scrollY = window.pageYOffset;
    else if (document.documentElement && document.documentElement.scrollTop)
  		this.scrollY = document.documentElement.scrollTop;
  	else if (document.body && document.body.scrollTop) 
  		this.scrollY = document.body.scrollTop; 
  	else if (window.scrollY) this.scrollY = window.scrollY;
  },
  
  getAll: function () {
    this.getWinWidth(); this.getWinHeight();
    this.getScrollX();  this.getScrollY();
  }
  
}


var menuLayers = {
  timer: null,
  activeMenuID: null,
  show: function(id, e) {
    var mnu = document.getElementById? document.getElementById(id): null;
    if (!mnu) return;
    this.activeMenuID = id;
    if ( mnu.onmouseout == null ) mnu.onmouseout = this.mouseoutCheck;
    if ( mnu.onmouseover == null ) mnu.onmouseover = this.clearTimer;
    viewport.getAll();
    this.position(mnu,e);
  },
  
  hide: function() {
    this.clearTimer();
    if (this.activeMenuID && document.getElementById) 
      this.timer = setTimeout("document.getElementById('"+menuLayers.activeMenuID+"').style.visibility = 'hidden'", 300);
  },
  
  position: function(mnu, e) {
    this.timer = setTimeout("document.getElementById('" + menuLayers.activeMenuID + "').style.visibility = 'visible'", 100);
  },
  
  mouseoutCheck: function(e) {
    e = e? e: window.event;
    // is element moused into contained by menu? or is it menu (ul or li or a to menu div)?
    var mnu = document.getElementById(menuLayers.activeMenuID);
    var toEl = e.relatedTarget? e.relatedTarget: e.toElement;
    if ( mnu != toEl && !menuLayers.contained(toEl, mnu) ) menuLayers.hide();
  },
  
  // returns true of oNode is contained by oCont (container)
  contained: function(oNode, oCont) {
    if (!oNode) return; // in case alt-tab away while hovering (prevent error)
    while ( oNode = oNode.parentNode ) 
      if ( oNode == oCont ) return true;
    return false;
  },

  clearTimer: function() {
    if (menuLayers.timer) clearTimeout(menuLayers.timer);
  }
  
}