接前代码

function outputFolderLink() {
    if(this.hreference && this.target) {
        doc.write("<A HREF='" + this.hreference + "' TARGET=\""+this.target.name+"\" ")

        if(browserVersion > 0) {
            doc.write("onClick='JavaScript: clickOnFolder("+this.id+")'")
        }
        doc.write(">")
    }
    else
        doc.write("<A>")
}


function addChild(childNode) {
       selectfile[fEntries]=childNode.desc;
       fEntries++;
       this.children[this.nChildren] = childNode;
       this.nChildren++;
       return(childNode);
}


function folderSubEntries() {
    var i = 0;
    var se = this.nChildren;

    for(i = 0; i < this.nChildren; i++) {
        if(this.children[i].children) //is a folder
            se = se + this.children[i].subEntries();
    }

    return(se)
}


// Definition of class Item (a document or link inside a Folder)

function Item(itemDescription, hreference, itemLink, itemImg,parentid) // Constructor
{
    // constant data
    this.desc = itemDescription
    this.link = itemLink
    this.hreference = hreference;
    this.id =index;
    this.navObj = 0;  //initialized in render()
    this.iconImg = 0; //initialized in render()

    // iconSrc俊 瘤沥登绰 捞固瘤 颇老阑 阿 酒捞袍俊 嘎霸 瘤沥且 荐 乐档废 茄促 (格钎)
    this.iconSrc = itemImg;

    // methods
    this.initialize = initializeItem ;
    this.createIndex = createEntryIndex;
    this.hide = hideItem;
    this.display = display;
    this.renderOb = drawItem;
    this.totalHeight = totalHeight;

    this.parentid=parentid;
    //alert(this.parent);
}


function hideItem() {
    if(browserVersion == 1) {
        if(this.navObj.style.display == "none")
            return;
        this.navObj.style.display = "none"
    }
    else {
        if(this.navObj.visibility == "hiden")
            return;
        this.navObj.visibility = "hiden";
    }
}


function initializeItem(level, lastNode, leftSide) {
    this.createIndex();

    if(level > 0) {
        if(lastNode) { //the last 'brother' in the children array
            this.renderOb(leftSide + "<IMG SRC='"+imageURL+"ftv2lastnode.gif' WIDTH=16 HEIGHT=22>")
            leftSide = leftSide + "<IMG SRC='"+imageURL+"ftv2blank.gif' WIDTH=16 HEIGHT=22>"
        }
        else {
            this.renderOb(leftSide + "<IMG SRC='"+imageURL+"ftv2node.gif' WIDTH=16 HEIGHT=22>")
            leftSide = leftSide + "<IMG SRC='"+imageURL+"ftv2vertline.gif' WIDTH=16 HEIGHT=22>"
        }
    }
    else
        this.renderOb("")
}


function drawItem(leftSide) {

    if(browserVersion == 2)
        doc.write("<LAYER ID='item" + this.id + "' TOP=" + doc.yPos + " VISIBILITY=hiden>");

    doc.write("<TABLE ");
    if(browserVersion == 1)
        doc.write(" ID='item" + this.id + "' STYLE='position:block;' ");
    doc.write(" BORDER=0 CELLSPACING=0 CELLPADDING=0>");
    doc.write("<TR><TD>");
    doc.write(leftSide);

    if(this.link != "") doc.write("<A  onclik=\'veiwFile("+this.id+")\'  HREF=" + this.link + ">");
    doc.write("<IMG ID='itemIcon"+this.id+"' ")
    doc.write("SRC='"+this.iconSrc+"' BORDER=0>")

    if(this.link != "")
        doc.write("</A>");

    doc.write("</TD><TD NOWRAP>");
    doc.write("<DIV CLASS=\"fldritem\">");
    if(USETEXTLINKS) {
        if(this.link != "")
               doc.write("<A  onclick=\'veiwFile("+this.id+")\' HREF=" + this.link + '><font size="2" color="'+linkColor+'">'+ this.desc + "</font></A>");
        else
            doc.write(this.desc);
    }
    else {
        doc.write(this.desc);
    }

    doc.write("</DIV>");
    doc.write("</TABLE>")

    if(browserVersion == 2)
        doc.write("</layer>");

    if(browserVersion == 1) {
        this.navObj = doc.all["item"+this.id]
        this.iconImg = doc.all["itemIcon"+this.id]
    }
    else if(browserVersion == 2) {
        this.navObj = doc.layers["item"+this.id];
        this.iconImg = this.navObj.document.images["itemIcon"+this.id];
        doc.yPos = doc.yPos+this.navObj.clip.height;
    }
}

function addposition(id,str1){
    if(id>0){
       clickedFolder = indexOfEntries[id];
       parentid=clickedFolder.parentid;
       parentname=indexOfEntries[parentid];
       pa=parentname.desc;
       if(parentid==0)str=pa+str1;
       else str='</font><font size=\"2\" color=\"#8F8F8F\">—></font><font size=\"2\" color="#AA0000">'+pa+str1;
       addposition(parentid,str);

    }
}
var str="";
function veiwFile (msg) {
    var typeLogo=typeof top.logo;
    if(typeLogo=="undefined")return;
    var tpyeFrame=typeof  top.logo.top1;
    if(tpyeFrame=="undefined")return;
    objDocument= top.logo.top1;
    var folderText="";
    if(msg==0)folderText=selectfile[msg];
    else {
         str='</font><font size=\"2\" color=\"#8F8F8F\">—></font></font><font size=\"2\" color="#AA0000">'+selectfile[msg];
         addposition(msg,str);
         folderText=str;
    }
    objDocument.document.open();
    objDocument.document.write('<font size=\"2\" color=\"#8F8F8F\"> 当前位置：  </font>  <font size=\"2\" color="#AA0000"> '+folderText+"</font>");
    objDocument.document.close();
}

// Methods common to both objects (pseudo-inheritance)
function display() {
    if(browserVersion == 1)
        this.navObj.style.display = "block";
    else
        this.navObj.visibility = "show";
}


function createEntryIndex() {
    indexOfEntries[nEntries] = this;
    nEntries++;
}


// total height of subEntries open
function totalHeight() { //used with browserVersion == 2
    var h = this.navObj.clip.height;
    var i = 0;

    if(this.isOpen) { // is a folder and _is_ open
        for(i = 0 ; i < this.nChildren; i++)
            h = h + this.children[i].totalHeight();
    }
    return h
}


// Events

function clickOnFolder(folderId) {
    var clicked = indexOfEntries[folderId];
    if(!clicked.isOpen)
        clickOnNode(folderId);
    if(clicked.isSelected)
        return;
}


function clickOnNode(folderId) {
    var clickedFolder = 0;
    var state = 0;
    clickedFolder = indexOfEntries[folderId];
    state = clickedFolder.isOpen;
    if (!state){
         if(clickedFolder.target)clickedFolder.target.location=clickedFolder.hreference; //点击folder时显示相关链接页面
         veiwFile(folderId);
     }
    clickedFolder.setState(!state); //open<->close
}


function initializeDocument() {
    if(doc.all)
        browserVersion = 1; //IE4
    else if(doc.layers)
        browserVersion = 2; //NS4
    else
        browserVersion = 0; //other

    foldersTree.initialize(0, 1, "");
    //foldersTree.display();

    if(browserVersion > 0) {
        doc.write("<LAYER TOP="+indexOfEntries[nEntries-1].navObj.top+"> </LAYER>");

        // close the whole tree
        clickOnNode(0);

        // open the root folder
        clickOnNode(0);
    }
}


// Auxiliary Functions for Folder-Treee backward compatibility
function gFldr(description, hreference,parentid,target) {
        var des;
        index++;
        if(fEntries==0){
           selectfile[fEntries]=description;
           fEntries++;
        }
        des=description;
    folder = new Folder(des, hreference,parentid,target);
    return(folder);
}


function gLnk(target, description, linkData, itemImg,parentid) {
    fullLink = ""

    if(target == 0 ||target=="") {
        if(linkData != "")
            fullLink = "'"+linkData+"' TARGET=\"_blank\"";//显示在新开的窗体中
        else
            fullLink = "";
    }
    if(target == 1) {
        if(linkData != "" )
            fullLink = "'"+linkData+"' TARGET=\"_slef\"";//显示在表单所在的框架或窗体中
        else
            fullLink = "";
    }
    else if(target == 2) {
        if(linkData != "")
            fullLink = "'"+linkData+"' TARGET=\"_parent\""; //显示在包含表单的框架的父框架中
        else
            fullLink = "";
    }
    else if(target == 3) {
        if(linkData != "")
            fullLink = "'"+linkData+"' TARGET=\"_top\"";//显示在顶层窗体中
        else
            fullLink = "";
    }

    else {//alert(target);
        if(linkData != "")
            fullLink = "'"+linkData+"' TARGET="+target;//显示在target窗体中
        else
            fullLink = "";
    }
    index++; //当前节点编号

    linkItem = new Item(description, linkData, fullLink, itemImg,parentid)
    return linkItem
}


function insFldr(parentFolder, childFolder,target,hreference) {
        var child;
        var desc;
        parentid=parentFolder.id;
        child=gFldr(childFolder,hreference,parentid,target);
    return(parentFolder.addChild(child));
}


function insDoc(parentFolder,target, description, linkData, itemImg) {
        var document;
        var itemImg;
        itemImg=imageURL+"bu.gif";
        var desc;
        parentid=parentFolder.id;
        document=gLnk(target, description, linkData, itemImg,parentid);
    parentFolder.addChild(document);
}

function setObjDocument(msg){
if (msg!=null){
   objDocument=msg;
}
}

//设置展开、收缩图片路径
function setImageURL(msg){
if (msg==null){
     imageURL="../leftfiles/images/";
}else imageURL=msg;
}

//设置超链接文本颜色
function setLinkColor(msg){
   linkColor=msg;
}
function setFloderColor(msg){
   floderColor=msg;
}
// Global variables

USETEXTLINKS = 1;
indexOfEntries = new Array;
nEntries = 0;
index=-1;   //节点编号
doc = document;
browserVersion = 0;
selectedFolder = 0;
selectfile=new Array;
fEntries=0;
var objDocument,imageURL;
var linkColor="#085dde";
var floderColor="#292c08";
var type1=typeof top.logo;

if (type1=="undefined"){
    objDocument=null;
}

if(imageURL==null){
   setImageURL(imageURL);
}

原文转自：http://www.ltesting.net