var persisteduls = new Object()
var ddtreemenu = new Object()

ddtreemenu.closefolder = "/Web/plus.gif" //set image path to "closed" folder image
ddtreemenu.openfolder = "/Web/min.gif" //set image path to "open" folder image

ddtreemenu.createTree = function(treeid, enablepersist, persistdays)
{
	var ultags=document.getElementById(treeid).getElementsByTagName("ul")
	if (typeof persisteduls[treeid]=="undefined")
		persisteduls[treeid] = (enablepersist == true && ddtreemenu.getCookie(treeid) != "") ? ddtreemenu.getCookie(treeid).split(",") : ""
	for (var i = 0; i < ultags.length; i++)
		ddtreemenu.buildSubTree(treeid, ultags[i], i)
	if (enablepersist == true)
	{ //if enable persist feature
		var durationdays = (typeof persistdays == "undefined") ? 1 : parseInt(persistdays)
		ddtreemenu.dotask(window, function() {ddtreemenu.rememberstate(treeid, durationdays)}, "unload") //save opened UL indexes on body unload
	}
}

ddtreemenu.buildSubTree = function(treeid, ulelement, index)
{
	ulelement.parentNode.className = "submenu"
	if (typeof persisteduls[treeid] == "object")
	{ //if cookie exists (persisteduls[treeid] is an array versus "" string)
		if (ddtreemenu.searcharray(persisteduls[treeid], index))
		{
			ulelement.setAttribute("rel", "open")
			ulelement.style.display = "block"
			ulelement.parentNode.style.backgroundImage = "url(" + ddtreemenu.openfolder + ")"
		}
		else
			ulelement.setAttribute("rel", "closed")
	} //end cookie persist code
	else if (ulelement.getAttribute("rel") == null || ulelement.getAttribute("rel") == false) //if no cookie and UL has NO rel attribute explicted added by user
		ulelement.setAttribute("rel", "closed")
	else if (ulelement.getAttribute("rel") == "open") //else if no cookie and this UL has an explicit rel value of "open"
		ddtreemenu.expandSubTree(treeid, ulelement) //expand this UL plus all parent ULs (so the most inner UL is revealed!)
	ulelement.parentNode.onclick = function(e)
	{
		var submenu = this.getElementsByTagName("ul")[0]
		if (submenu.getAttribute("rel") == "closed")
		{
			submenu.style.display = "block"
			submenu.setAttribute("rel", "open")
			ulelement.parentNode.style.backgroundImage = "url(" + ddtreemenu.openfolder + ")"
		}
		else if (submenu.getAttribute("rel") == "open")
		{
			submenu.style.display = "none"
			submenu.setAttribute("rel", "closed")
			ulelement.parentNode.style.backgroundImage = "url(" + ddtreemenu.closefolder + ")"
		}
		ddtreemenu.preventpropagate(e)
	}
	ulelement.onclick = function(e)
	{
		ddtreemenu.preventpropagate(e)
	}
}

ddtreemenu.expandSubTree = function(treeid, ulelement)
{ //expand a UL element and any of its parent ULs
	var rootnode = document.getElementById(treeid)
	var currentnode = ulelement
	currentnode.style.display = "block"
	currentnode.parentNode.style.backgroundImage = "url(" + ddtreemenu.openfolder + ")"
	while (currentnode != rootnode)
	{
		if (currentnode.tagName == "UL")
		{ //if parent node is a UL, expand it too
			currentnode.style.display = "block"
			currentnode.setAttribute("rel", "open") //indicate it's open
			currentnode.parentNode.style.backgroundImage = "url(" + ddtreemenu.openfolder + ")"
		}
		currentnode = currentnode.parentNode
	}
}

ddtreemenu.rememberstate = function(treeid, durationdays)
{ //store index of opened ULs relative to other ULs in Tree into cookie
	var ultags = document.getElementById(treeid).getElementsByTagName("ul")
	var openuls = new Array()
	for (var i = 0; i < ultags.length; i++)
	{
	if (ultags[i].getAttribute("rel") == "open")
		openuls[openuls.length] = i //save the index of the opened UL (relative to the entire list of ULs) as an array element
	}
	if (openuls.length == 0) //if there are no opened ULs to save/persist
		openuls[0] = "none open" //set array value to string to simply indicate all ULs should persist with state being closed
	ddtreemenu.setCookie(treeid, openuls.join(","), durationdays) //populate cookie with value treeid=1,2,3 etc (where 1,2... are the indexes of the opened ULs)
}

////A few utility functions below//////////////////////

ddtreemenu.getCookie = function(Name)
{ //get cookie value
	var re = new RegExp(Name + "=[^;]+", "i"); //construct RE to search for target name/value pair
	if (document.cookie.match(re)) //if cookie found
		return document.cookie.match(re)[0].split("=")[1] //return its value
	return ""
}

ddtreemenu.setCookie = function(name, value, days)
{ //set cookei value
	var expireDate = new Date()
	//set "expstring" to either future or past date, to set or delete cookie, respectively
	var expstring = expireDate.setDate(expireDate.getDate() + parseInt(days))
	document.cookie = name + "=" + value + "; expires=" + expireDate.toGMTString() + "; path=/";
}

ddtreemenu.searcharray = function(thearray, value)
{ //searches an array for the entered value. If found, delete value from array
	var isfound=false
	for (var i=0; i < thearray.length; i++)
	{
		if (thearray[i] == value)
		{
			isfound = true
			thearray.shift() //delete this element from array for efficiency sake
			break
		}
	}
	return isfound
}

ddtreemenu.preventpropagate = function(e)
{ //prevent action from bubbling upwards
	if (typeof e != "undefined")
		e.stopPropagation()
	else
		event.cancelBubble = true
}

ddtreemenu.dotask = function(target, functionref, tasktype)
{ //assign a function to execute to an event handler (ie: onunload)
	var tasktype=(window.addEventListener) ? tasktype : "on" + tasktype
	if (target.addEventListener)
		target.addEventListener(tasktype, functionref, false)
	else if (target.attachEvent)
		target.attachEvent(tasktype, functionref)
}