本原码从网上下载，经本人改写，功能更强大，使用更方便，可以有无限级目录，一次性载入，可以分别设置树结点和叶结点的颜色及图标，可以展开和收缩，可以显示当前所处的路径位置，点击树结点时只在展开时显示树结点的超链接，不过，据测试，一次性载入500个节点时浏览器会显示“该脚本会使浏览器变慢”的提示，不过，选择不取消执行不会影响浏览器的性能。
function Folder(folderDescription, hreference,parentid,target) {
   //constant data;

   this.desc = folderDescription;
   this.parentid=parentid;
   this.hreference = hreference;
   this.target=target;
   this.id = index;
   this.navObj = 0;
   this.iconImg = 0;
   this.nodeImg = 0;
   this.isLastNode = 0;

   // dynamic data
   this.isRoot = true;
   this.isOpen = true;
   this.iconSrc=imageURL+"ftv2folderopen.gif";
   this.iconRoot =imageURL+"ftv2folderopen.gif";

   this.children = new Array;
   this.nChildren = 0;

   // methods
   this.initialize = initializeFolder;
   this.setState = setStateFolder;
   this.addChild = addChild;

   this.createIndex = createEntryIndex;
   this.hide = hideFolder;
   this.display = display;
   this.renderOb = drawFolder;
   this.totalHeight = totalHeight;
   this.subEntries = folderSubEntries;
   this.outputLink = outputFolderLink;

}


function setStateFolder(isOpen) {
   var subEntries;
   var totalHeight;
   var fIt = 0;
   var i = 0;

   if(isOpen == this.isOpen)
       return;

   if(browserVersion == 2) {
       totalHeight = 0
       for(i = 0; i < this.nChildren; i++)
           totalHeight = totalHeight + this.children[i].navObj.clip.height;
       subEntries = this.subEntries();

       if(this.isOpen)
           totalHeight = 0 - totalHeight;

       for(fIt = this.id + subEntries + 1; fIt < nEntries; fIt++)
           indexOfEntries[fIt].navObj.moveBy(0, totalHeight);
   }

   this.isOpen = isOpen;
   propagateChangesInState(this);
}


function propagateChangesInState(folder) {

   var i = 0;
   if(folder.isOpen) {
       if(folder.nodeImg) {
           if(folder.isLastNode)
               folder.nodeImg.src = imageURL+"ftv2mlastnode.gif";
           else
               folder.nodeImg.src = imageURL+"ftv2mnode.gif";
       }

       if(this.isRoot)
&nb