新手上路~ 求大神帮忙完成 JS 三级下拉菜单


<!doctype html>
<html lang="zh-cn">
<head>
    <meta charset="utf-8">
<style>ul{display:none;}</style>
    <script src="http://code.jquery.com/jquery-1.11.1.min.js"></script>
</head>
<body>
<script>
    $(document).ready(function(){
var con = $("#dorpmenu_dolphin4");
con.on({
"mouseenter":function(e){
$(this).siblings("ul").show();
}
},"a");
con.on("mouseleave",function(e){
$(this).find("ul").hide();
});
    });
    </script>
    <div id="dorpmenu_dolphin4" class="dorpmenu_dolphin">
     <a href="#">产品中心</a>
        <ul>
            <li>
                <a href="">123</a>
                <ul>
                    <li>
                     <a href="">147</a>
                        <ul>
                            <li>
                                <a href="">111111</a>
                                <ul>
                                    <li><a href="">22222</a></li>
                                </ul>
                            </li>
                        </ul>
                    </li>
                </ul>
            </li>
            <li>
             <a href="">456</a>
                <ul>
                    <li><a href="">467878</a></li>
                </ul>
            </li>
            <li><a href="">789</a></li>
            <li><a href="">561</a></li>
            <li><a href="">635</a></li>
            <li>
             <a href="">654</a>
                <ul>
                    <li><a href="">66666</a></li>
                </ul>
            </li>
        </ul>
    </div>
</body>
</html>