jquery 无限级下拉菜单实例代码分析

var menuData = [
{id:0,pid:-1,name:"订购产品",url:"",children:[
    {id:1,pid:0,name:"电脑配件",url:"http://www.jb200.com",children:[
{id:20,pid:1,name:"cpu",url:"http://www.jb200.com",children:[
{id:30,pid:20,name:"Intel",url:"http://www.jb200.com",children:[
    {id:3000,pid:30,name:"Intel 01",url:""},
    {id:3001,pid:30,name:"Intel 02",url:""},
    {id:3002,pid:30,name:"Intel 03",url:""},
    {id:3003,pid:30,name:"Intel 04",url:""},
    {id:3004,pid:30,name:"Intel 05",url:""},
    {id:3005,pid:30,name:"Intel 06",url:""},
    {id:3006,pid:30,name:"Intel 07",url:""},
    {id:3007,pid:30,name:"Intel 08",url:""},
    {id:3008,pid:30,name:"Intel 09",url:""}
]},
{id:31,pid:20,name:"AMD",url:"http://www.jb200.com",children:[
    {id:3100,pid:31,name:"AMD 01",url:""},
    {id:3101,pid:31,name:"AMD 02",url:""},
    {id:3102,pid:31,name:"AMD 03",url:""},
    {id:3103,pid:31,name:"AMD 04",url:""},
    {id:3104,pid:31,name:"AMD 05",url:""},
    {id:3105,pid:31,name:"AMD 06",url:""},
    {id:3106,pid:31,name:"AMD 07",url:""},
    {id:3107,pid:31,name:"AMD 08",url:""},
    {id:3108,pid:31,name:"AMD 09",url:""}
]}
]},
{id:21,pid:1,name:"内存",url:"http://www.jb200.com"},
{id:22,pid:1,name:"硬盘",url:"http://www.jb200.com"},
{id:23,pid:1,name:"主板",url:"http://www.jb200.com"},
{id:24,pid:1,name:"显卡",url:"http://www.jb200.com"},
{id:25,pid:1,name:"显示器",url:"http://www.jb200.com"},
{id:26,pid:1,name:"主机箱",url:"http://www.jb200.com"},
{id:27,pid:1,name:"主机箱电源",url:"http://www.jb200.com"},
{id:28,pid:1,name:"键鼠(有线)",url:"http://www.jb200.com"},
{id:29,pid:1,name:"键鼠(无线)",url:"http://www.jb200.com"}
    ],url:"http://www.jb200.com"},
    {id:101,pid:0,name:"监控器材",children:[
{id:102,pid:101,name:"摄像头",url:"http://www.jb200.com"},
{id:103,pid:101,name:"摄像头",url:"http://www.jb200.com"},
{id:104,pid:101,name:"摄像头",url:"http://www.jb200.com"},
{id:112,pid:101,name:"摄像头",url:"http://www.jb200.com"},
{id:113,pid:101,name:"摄像头",url:"http://www.jb200.com"},
{id:114,pid:101,name:"摄像头",url:"http://www.jb200.com"},
{id:115,pid:101,name:"摄像头",url:"http://www.jb200.com"},
{id:116,pid:101,name:"摄像头",url:"http://www.jb200.com"},
{id:117,pid:101,name:"摄像头",url:"http://www.jb200.com"}
    ],url:"http://www.jb200.com"},
    {id:201,pid:0,name:"数码产品",children:[
{id:202,pid:201,name:"摄像头",url:"http://www.jb200.com"}
    ],url:"http://www.jb200.com"},
    {id:301,pid:0,name:"网络产品",children:[
{id:302,pid:301,name:"摄像头",url:"http://www.jb200.com"}
    ],url:"http://www.jb200.com"},
    {id:401,pid:0,name:"打印耗材",children:[
{id:402,pid:401,name:"打印机",url:"http://www.jb200.com"},
{id:403,pid:401,name:"油墨",url:"http://www.jb200.com"},
{id:404,pid:401,name:"纸张",url:"http://www.jb200.com"},
{id:405,pid:401,name:"摄像头",url:"http://www.jb200.com"},
{id:406,pid:401,name:"摄像头",url:"http://www.jb200.com"},
{id:407,pid:401,name:"摄像头",url:"http://www.jb200.com"},
{id:408,pid:401,name:"摄像头",url:"http://www.jb200.com"}
    ],url:"http://www.jb200.com"}
]},
{id:1000,pid:-1,name:"我的订单",url:"",children:[
    {id:1001,pid:1000,name:"已过期订单",url:""},
    {id:1001,pid:1000,name:"已付款订单",url:""}
]},
{id:2000,pid:-1,name:"公司信息",url:"",children:[
    {id:2001,pid:2000,name:"最新新闻",url:""},
    {id:2002,pid:2000,name:"公司地址",url:""}
]}
];

(function($){
    $.fn.extend({
menu:function(options){
var defaults = {
    data:[],
    ulId:"baseMenu"
};
var options = $.extend(defaults, options);
// 开始拼接ul,li
$.each(options.data,function(i,v){
    var li = $("<li id='"+options.data[i].id+"' name='"+options.data[i].pid+"'></li>");
    var _a = $("<a>"+options.data[i].name+"</a>");
    _a.attr("href",options.data[i].url)
.appendTo(li);

    _each(options.data[i],li);
    li.appendTo($("#"+options.ulId));
});
// 给li添加事件
$(this).find("li").hover(function(){
    var id = $(this).attr("id");
    $(this).find("ul[name='"+id+"']").show();
},function(){
    var id = $(this).attr("id");
    $(this).find("ul[name='"+id+"']").hide();
});
}
    });
})(jQuery);

function _each(data,li){
    if(data==undefined||data.children==undefined){
return false;
    }
    var ul = $("<ul name='"+data.id+"' style='display:none;'></ul>");

    $.each(data.children,function(i,v){
var _li = $("<li id='"+data.children[i].id+"' name='"+data.children[i].pid+"'></li>");
var _a = $("<a>"+data.children[i].name+"</a>");
_a.attr("href",data.children[i].url)
.attr("target","_blank")
.appendTo(_li);

if(data.children[i].children!=undefined){
_each(data.children[i],_li);
}
_li.appendTo(ul);
    });
    ul.appendTo(li);
}

$(function() {
    $("#menu").menu({data:menuData,ulId:"baseMenu"});
});

ul,li{list-style:none;padding:0px;margin:0px;}
#menu *{line-height:30px;}
#menu a{text-decoration:none;}
#menu ul{text-align:left;}
#menu>ul>li{text-align:center;width:80px;float:left;}
#menu>ul>li>a{color:#000;}
#menu>ul>li:hover{background:#F0F0F0;}
#menu>ul>li ul{display:none;width:150px;position:absolute;background:#c1cd94;box-shadow:2px 2px 2px #000;-webkit-box-shadow:2px 2px 2px #000;
　　-moz-box-shadow:2px 2px 2px #123;}
#menu>ul>li>ul li{padding-left:5px; position:relative;}
#menu>ul>li>ul li>a{color:#000;}
#menu>ul>li>ul li:hover{background:#d3dbb3;}
#menu>ul>li>ul>li ul{left:150px; top:0px;}