树菜单js网上多得是，自己写了一个树菜单类，自认为还不错，公开大家共享和探讨，和大家一起进步最快乐！！

<!--
functionDtree(){
this.MenuGroupClose="images/treeview_close.gif";//菜单关闭图标
this.MenuGroupOpen="images/treeview_open.gif";//菜单打开图标
this.MenuItemClass="";//菜单项样式
this.MenuItemInfoClass="";//菜单链接样式
this.MenuItemlPad="12px";//下级菜单缩进仁值
this.DefaultGroupState=false;//菜单组装入时默认状态
document.write("<divid=\"treeroot\"></div>");
this.Node=document.getElementById("treeroot");
//0结点DOM对像,数组1为连接显示，2为连接href，3为连接target,4为连接显示前图标
this.AddItem=function(menuinfo){
vardiv=creatediv();
vardiv1=creatediv();
varico=[this.MenuGroupClose,this.MenuGroupOpen];
div.className=this.MenuItemClass;
div1.style.marginLeft=this.MenuItemlPad;
div1.style.display=this.DefaultGroupState?"":"none";
varNode=menuinfo[0]?menuinfo[0][1]:this.Node;
variteminfo="";
if(menuinfo[4])iteminfo="<imgsrc=\""+menuinfo[4]+"\"align=\"absmiddle\">";
if(menuinfo[2])iteminfo+="<ahref=\""+menuinfo[2]+"\"target=\""+menuinfo[3]+"\"class=\""+this.MenuItemInfoClass+"\">";
iteminfo+=menuinfo[1];
if(menuinfo[2])iteminfo+="</a>";
div.innerHTML=iteminfo;
Node.appendChild(div);
Node.appendChild(div1);
if(menuinfo[0]){
if(!menuinfo[0][0].havechild){
varas=document.createElement("img");
as.src=ico[1];
as.align="absmiddle";
as.onclick=function(){
swapshow(Node,as,ico);
}
menuinfo[0][0].insertBefore(as,menuinfo[0][0].firstChild);
as.insertAdjacentText("afterEnd","");
menuinfo[0][0].havechild=true;
}
}
return[div,div1];
}

functioncreatediv(){
vardiv=document.createElement("div");
returndiv;
}

functionswapshow(obj,ico,oo){
if(obj.style.display!=""){
obj.style.display="";
ico.src=oo[0];
}
else{
obj.style.display="none";
ico.src=oo[1];
}
}
}
-->