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){

        ddtreemenu.flatten(treeid,"collapse")

        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+")"

           ddtreemenu.expandSubTree(treeid, ulelement)

//       }
//        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.flatten(treeid,"collapse")
        ddtreemenu.expandSubTree(treeid, ulelement)
        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.flatten=function(treeid, action){ //expand or contract all UL elements
    var ultags=document.getElementById(treeid).getElementsByTagName("ul")
    for (var i=0; i<ultags.length; i++){
        ultags[i].style.display=(action=="expand")? "block" : "none"
        var relvalue=(action=="expand")? "open" : "closed"
        ultags[i].setAttribute("rel", relvalue)
        ultags[i].parentNode.style.backgroundImage=(action=="expand")? "url("+ddtreemenu.openfolder+")" : "url("+ddtreemenu.closefolder+")"
    }
}

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)
}