先看效果（两种，1：自己写样式，写交互，2.用jQueryUI 的menu），如下图
第一种： 
第二种： 
第一种样式：
然后就开始准备了，单村用js和css也可以写出来，不过既然有jquery我就偷个懒吧
1.去http://jquery.com/download/下载jquery
2.开始写html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> <!-- 设置编码-->
<link rel="stylesheet" type="text/css" href="css/style.css" rel="external nofollow" rel="external nofollow" ><!-- 引用css样式-->
<script type="text/javascript" src="js/jquery-3.1.0.min.js"></script><!-- 引入jquery-->
<script type="text/javascript" src="js/js.js"></script><!--引入自己的js -->
<title>菜单测试</title>
</head>
<body>
<ul><!-- 菜单栏基本样式-->
<li class="hmain">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >菜单1</a>
<ul>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单1</a>
</li>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单2</a>
</li>
</ul>
</li>
<li class="hmain">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >菜单2</a>
<ul>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单1</a>
</li>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单2</a>
</li>
</ul>
</li>
<li class="hmain">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >菜单3</a>
<ul>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单1</a>
</li>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单2</a>
</li>
</ul>
</li>
</ul>
</body>
</html>
3.写css样式
ul,li{
list-style: none; /*取消ul,li前面的小点 */
}
ul{
padding: 0; /*取消ul的缩进（默认会有一个缩进）*/
margin: 0;
}li{
background-color: #eeeeee;
}
a{
text-decoration: none; /* 取消超链接的下划线*/
padding-left: 20px;
display: block;
width: 80px;
padding-top:3px;
padding-bottom: 3px;
}
.hmain{
background-image: url(../images/title.jpg); /* 设置导航背景*/
background-repeat: repeat-x; /* 设置背景图片的排列方式*/
width: 100px;
}
.hmain a{
color: red;
}
.hmain li a{
color: black;
}
.hmain ul{
display: none; /* 默认隐藏二级菜单栏*/
}.hmain{
float: left; /* 导航定位（水平）*/
margin-right: 2px;
}
4到了交互的时候了自己的js,一句话搞定，先找到ul下的a，绑定鼠标滑过事件
$(document).ready(function(){
var mean = $(".hmain>a");
mean.on("mouseenter mouseleave", function(){
var ulNode = $(this).next("ul");
ulNode.toggle("normal");
});
});
初学者，有什么不对的地方请指出，谢谢
第二种样式：
然后就开始准备了，单村用js和css也可以写出来，不过既然有jquery我就偷个懒吧
1.去http://jquery.com/download/下载jquery(需要一个文件jquery-3.1.0.min.js)
去http://jqueryui.com/download/下载jqueryUI(需要两个文件jquery-ui.min.js，jquery-ui.min.css)
2.开始写html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> <!-- 设置编码-->
<script type="text/javascript" src="js/jquery-3.1.0.min.js"></script><!-- 引入jquery-->
<script type="text/javascript" src="js/jquery-ui.min.js"></script><!-- 引入jqueryui-->
<script type="text/javascript" src="js/js.js"></script><!--引入自己的js -->
<link rel="stylesheet" type="text/css" href="css/jquery-ui.min.css" rel="external nofollow" ><!-- 引用jqueryUIcss样式-->
<link rel="stylesheet" type="text/css" href="css/style.css" rel="external nofollow" rel="external nofollow" ><!-- 引用css样式-->
<title>菜单测试</title>
</head>
<body>
<ul class="menu"><!-- 菜单栏基本样式-->
<li class="hmain">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >菜单1</a>
<ul>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单1</a>
</li>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单2</a>
</li>
</ul>
</li>
<li class="hmain">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >菜单2</a>
<ul>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单1</a>
</li>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单2</a>
</li>
</ul>
</li>
<li class="hmain">
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >菜单3</a>
<ul>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单1</a>
</li>
<li>
<a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >子菜单2</a>
</li>
</ul>
</li>
</ul>
</body>
</html>
3.写css样式
ul,li{
list-style: none; /*取消ul,li前面的小点 */
}
ul{
padding:; /*取消ul的缩进（默认会有一个缩进）*/
margin:;
}li{
background-color: #eeeeee;
}
a{
text-decoration: none; /* 取消超链接的下划线*/
padding-left: 20px;
display: block;
width: 80px;
padding-top:3px;
padding-bottom: 3px;
}
.hmain{
width: 100px;
}
.hmain a{
color: red;
}
.hmain li a{
color: black;
}
.hmain ul{
display: none; /* 默认隐藏二级菜单栏*/
}.hmain{
float: left; /* 导航定位（水平）*/
margin-right: 2px;
}
4.交互
$(document).ready(function(){
var menu = $(".menu");
menu.menu({position:{at: "left bottom"}});
});
很简单啦
