var currentMenu = null;

if (!document.getElementById) {
	document.getElementById = function() {
		return null;
	};
}

function initializeMenu(menuId, actuatorId) {
  var menu = document.getElementById(menuId);
  var actuator = document.getElementById(actuatorId);
  if (menu == null || actuator == null) return;

  actuator.onmouseover = function() {
    if (currentMenu) {
      if (currentMenu.filters) if (currentMenu.filters[0]) currentMenu.filters[0].Apply();
      currentMenu.style.visibility = "hidden";
      if (currentMenu.filters) if (currentMenu.filters[0]) currentMenu.filters[0].Play();
    }
    this.showMenu();
    a=0;
  };
  
  actuator.onmouseout = function() {
  	a=1;
  	setTimeout('if(a==1){currentMenu.style.visibility = "hidden"};',100);
  };
  menu.onmouseover = function() {
  	a=0;
  };
  menu.onmouseout = function() {
  	a=1;
  	setTimeout('if(a==1){currentMenu.style.visibility = "hidden"};',100);
  };
  
  actuator.showMenu = function() {
    menu.style.left = this.offsetLeft + "px";
    menu.style.top = this.offsetTop + this.offsetHeight + "px";
    if (menu.filters) if (menu.filters[0]) menu.filters[0].Apply();
	menu.style.visibility = "visible";
    if (menu.filters) if (menu.filters[0]) menu.filters[0].Play();
    currentMenu = menu;
  };
}

function loadMenus() {
  initializeMenu("aboutMenu", "aboutActuator");
  initializeMenu("visitMenu", "visitActuator");
  initializeMenu("peopleMenu", "peopleActuator");
  initializeMenu("newsMenu", "newsActuator");
  initializeMenu("publicationsMenu", "publicationsActuator");
  initializeMenu("managingMenu", "managingActuator");
  initializeMenu("mapMenu", "mapActuator");
}

// AJAX code forking
function getHTTPOject() {
	var xhr = false;
	if (window.ActiveXObject) {
		try {
			xhr = new ActiveXObject("Msxml2.XMLHTTP");
		} catch(e) {
			try {
				xhr = new ActiveXObject("Microsoft.XMLHTTP");
			} catch(e) {
				xhr = false;
			}
		}
	} else if (window.XMLHttpRequest) {
		try {
			xhr = new XMLHttpRequest();
		} catch(e) {
			xhr = false;
		}
	}
	return xhr;
}

// AJAX - Grabs a predefined file to pull back into the page
function grabFile(file) {
	var request = getHTTPOject();
	if (request) {
		request.onreadystatechange = function() {
		displayResponse(request);
		};
		request.open( "GET", file, true );
		request.send(null);
	}
}

//AJAX - Once the file is found this decides what to do with it.
function displayResponse(request) {
	if (request.readyState == 4) {
		document.getElementById("mainMenu").innerHTML = request.responseText;
		loadMenus();
	}
}

// Runs all the listed functions on the loading of the window

window.onload=function(){
	
	grabFile("/scripts/mainnav.html");
	
}