jq实现多级手风琴效果

/*左侧*/
.wrapper, .main {
    height: 100%;
    z-index: 9
}

.main {
    position: relative;
}

.main_L {
    width: 238px;
    height: 100%;
    background-color: #293038;
    position: absolute;
    left: 0;
    z-index: 99
}

.main_R {
    width: 100%;
    padding-left: 180px;
    z-index: -1;
}

.main_L a {
    color: #fff;
}

.main_list1 {
    cursor: pointer;
    background-color: #293038;
    color: #fff;
    text-align: center;
    font-size: 16px;
}

.mainList_a {
    display: block;
    width: 100%;
    height: 50px;
    line-height: 50px;
    position: relative;
    /*padding-left:30px;*/
}

.mainList_a b {
    width: 20px;
    height: 20px;
    background: url("left_bg.png") no-repeat -18px -658px;
    position: absolute;
    left: 10px;
    top: 50%;
    margin-top: -6px;
}

.mainList_a b.open {
    background: url("left_bg.png") no-repeat -25px -191px;
}

.main_list1 ul {
    display: none;
}

.main_list1 li a {
    display: block;
    height: 40px;
    line-height: 40px;
    font-size: 14px;
}

.main_list1 li a:hover {
    background-color: #208adb;
}
.header_user>a span{
    display: inline-block;
    width: 74%;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    *zoom: 1;
    *display: inline;
}
.main_list ul{display:none;}
.main_list2{padding-left:10px;}
.main_list3{padding-left:20px;}
.main_list4{padding-left:30px;}

left.css

/*公共样式--开始*/
html, body, div, ul, li, h1, h2, h3, h4, h5, h6, p, dl, dt, dd, ol, form, input, textarea, th, td, select {
    margin: 0;
    padding: 0;
}
*{box-sizing: border-box;}
html, body {
    min-height: 100%;
}

body {
    font-family: "Microsoft YaHei";
}

ul, li {
    list-style: none;
}

img {
    border: none;
    vertical-align: middle;
}

a {
    text-decoration: none;
    color: #232323;
}

table {
    border-collapse: collapse;
}

input, textarea {
    outline: none;
    border: none;
}

textarea {
    resize: none;
    overflow: auto;
}

.clearfix {
    zoom: 1;
}

.clearfix:after {
    content: ".";
    width: 0;
    height: 0;
    visibility: hidden;
    display: block;
    clear: both;
}

.fl {
    float: left
}

.fr {
    float: right
}

.tl {
    text-align: left;
}

.tc {
    text-align: center
}

.tr {
    text-align: right;
}

.ellipse {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/*公共样式--结束*/

public

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>头部和左侧菜单</title>
    <link rel="stylesheet" href="public.css"/>
    <link rel="stylesheet" href="left.css"/>
</head>
<body>
<div class="wrapper">
    <div class="main">
        <div class="main_L">
            <ul>
                <li class="main_list1">
                    <a href="javascript:void(0);" class="mainList_a"><b></b>222</a>
                    <ul>
                        <li class="main_list1 list_service">
                            <a href="javascript:void (0);" class="mainList_a">11</a>
                        </li>
                        <li class="main_list1 list_user">
                            <a href="javascript:void (0);" class="mainList_a"><b></b>11</a>
                            <ul>
                                <li class="main_list2">
                                    <a href="javascript:void (0);"  class="mainList_a"><b></b>11</a>
                                    <ul>
                                        <li class="main_list3">
                                            <a href="javascript:void (0);"  class="mainList_a">11</a>
                                        </li>
                                        <li class="main_list3"><a href="javascript:void (0);">11</a></li>
                                    </ul>
                                </li>
                                <li class="main_list2"><a href="javascript:void (0);">11</a></li>
                            </ul>
                        </li>
                        <li class="main_list1 list_order">
                            <a href="javascript:void (0);" class="mainList_a"><b></b>11</a>
                            <ul>
                                <li>
                                    <a href="javascript:void(0);"  class="mainList_a">11</a>
                                    <ul>
                                        <li><a href="javascript:void(0);">11</a></li>
                                        <li><a href="javascript:void(0);">11</a></li>
                                        <li><a href="javascript:void(0);">11</a></li>
                                    </ul>
                                </li>
                                <li><a href="javascript:void(0);">11</a></li>
                                <li><a href="javascript:void(0);">11</a></li>
                            </ul>
                        </li>
                        <li class="main_list1 list_news">
                            <a href="javascript:void (0);" class="mainList_a"><b></b>11</a>
                            <ul>
                                <li><a href="javascript:void(0);">11</a></li>
                            </ul>
                        </li>
                        <li class="main_list1 list_out">
                            <a href="javascript:void (0);" class="mainList_a"><b></b>11</a>
                            <ul>
                                <li>
                                    <a href="javascript:void(0);"  class="mainList_a">11</a>
                                    <ul>
                                        <li><a href="javascript:void(0);">11</a></li>
                                    </ul>
                                </li>
                            </ul>
                        </li>
                        <li class="main_list1 list_out">
                            <a href="javascript:void (0);" class="mainList_a"><b></b>11</a>
                            <ul>
                                <li>
                                    <a href="javascript:void(0);"  class="mainList_a">11</a>
                                    <ul>
                                        <li><a href="javascript:void(0);">查11</a></li>
                                        <li><a href="javascript:void(0);">11</a></li>
                                    </ul>
                                </li>
                            </ul>
                        </li>
                    </ul>

                </li>
            </ul>
        </div>
    </div>
</div>
</body>
<script src="jquery-1.11.3.min.js"></script>
<script src="common.js"></script>
</html>

$(function(){
    $(".mainList_a").on("click",function(){
        var $this=$(this);
        var $ul=$(this).siblings("ul");
        if($ul.css("display")=="none"){
            $this.siblings("ul").slideDown();
            $this.find("b").addClass("open");
        }else{
            $this.siblings("ul").slideUp();
            $this.find("b").removeClass("open");
        }
    });

    if (screen.width > 1180) {
        $("html").removeClass("screen1");
    } else {
        $("html").addClass("screen1");
    }

});