Help me on this

/***********************************************
* Switch Menu script- by Martial B of http://getElementById.com/
* Modified by Dynamic Drive for format & NS4/IE4 compatibility
* Visit http://www.dynamicdrive.com/ for full source code
***********************************************/

var persistmenu="yes" //"yes" or "no". Make sure each SPAN content contains an incrementing ID starting at 1 (id="sub1", id="sub2", etc)
var persisttype="sitewide" //enter "sitewide" for menu to persist across site, "local" for this page only

if (document.getElementById){ //DynamicDrive.com change
document.write('<style type="text/css">\n')
document.write('.fbsubmenu{display: none;}\n')
document.write('</style>\n')
}

function SwitchMenu(obj){
	if(document.getElementById){
	var el = document.getElementById(obj);
	var ar = document.getElementById("masterdiv").getElementsByTagName("span"); //DynamicDrive.com change
		if(el.style.display != "block"){ //DynamicDrive.com change
			for (var i=0; i<ar.length; i++){
				if (ar[i].className=="fbsubmenu") //DynamicDrive.com change
				ar[i].style.display = "none";
			}
			el.style.display = "block";
		}else{
			el.style.display = "none";
		}
	}
}

function get_cookie(Name) {
var search = Name + "="
var returnvalue = "";
if (document.cookie.length > 0) {
offset = document.cookie.indexOf(search)
if (offset != -1) {
offset += search.length
end = document.cookie.indexOf(";", offset);
if (end == -1) end = document.cookie.length;
returnvalue=unescape(document.cookie.substring(offset, end))
}
}
return returnvalue;
}

function onloadfunction(){
if (persistmenu=="yes"){
var cookiename=(persisttype=="sitewide")? "switchmenu" : window.location.pathname
var cookievalue=get_cookie(cookiename)
if (cookievalue!="")
document.getElementById(cookievalue).style.display="block"
}
}

function savemenustate(){
var inc=1, blockid=""
while (document.getElementById("sub"+inc)){
if (document.getElementById("sub"+inc).style.display=="block"){
blockid="sub"+inc
break
}
inc++
}
var cookiename=(persisttype=="sitewide")? "switchmenu" : window.location.pathname
var cookievalue=(persisttype=="sitewide")? blockid+";path=/" : blockid
document.cookie=cookiename+"="+cookievalue
}

if (window.addEventListener)
window.addEventListener("load", onloadfunction, false)
else if (window.attachEvent)
window.attachEvent("onload", onloadfunction)
else if (document.getElementById)
window.onload=onloadfunction

if (persistmenu=="yes" && document.getElementById)
window.onunload=savemenustate