js实现的常用的左侧导航效果

<!--左侧菜单-->
<div class="menu">
<ul class="menu_list">
<li class="even">
<p class="menu_title bgfs"><a href="#" target="_blank">服饰箱包</a></p>
<p class="menu_sort">
<a href="#" target="_blank">女装</a><a href="#" target="_blank">男装</a><a href="#" target="_blank">童装</a><a href="#" target="_blank">包包</a><br/>
<a href="#" target="_blank">鞋</a><a href="#" target="_blank">饰品</a>
</p>
</li>
<li class="odd">
<p class="menu_title bgjs"><a href="#" target="_blank">酒水饮料</a></p>
<p class="menu_sort">
<a href="#" target="_blank">女装</a><a href="#" target="_blank">男装</a><a href="#" target="_blank">童装</a><a href="#" target="_blank">包包</a><br/>
<a href="#" target="_blank">鞋</a><a href="#" target="_blank">饰品</a>
</p>
</li>
<li class="even">
<p class="menu_title bgjj"><a href="#" target="_blank">居家建材</a></p>
<p class="menu_sort">
<a href="#" target="_blank">女装</a><a href="#" target="_blank">男装</a><a href="#" target="_blank">童装</a><a href="#" target="_blank">包包</a><br/>
<a href="#" target="_blank">鞋</a><a href="#" target="_blank">饰品</a>
</p>
</li>
<li class="odd">
<p class="menu_title bgcy"><a href="#" target="_blank">餐饮娱乐</a></p>
<p class="menu_sort">
<a href="#" target="_blank">女装</a><a href="#" target="_blank">男装</a><a href="#" target="_blank">童装</a><a href="#" target="_blank">包包</a><br/>
<a href="#" target="_blank">鞋</a><a href="#" target="_blank">饰品</a>
</p>
</li>
<li class="even">
<p class="menu_title bgmr"><a href="#" target="_blank">美容保健</a></p>
<p class="menu_sort">
<a href="#" target="_blank">女装</a><a href="#" target="_blank">男装</a><a href="#" target="_blank">童装</a><a href="#" target="_blank">包包</a><br/>
<a href="#" target="_blank">鞋</a><a href="#" target="_blank">饰品</a>
</p>
</li>
<li class="odd">
<p class="menu_title bgjy"><a href="#" target="_blank">教育培训</a></p>
<p class="menu_sort">
<a href="#" target="_blank">女装</a><a href="#" target="_blank">男装</a><a href="#" target="_blank">童装</a><a href="#" target="_blank">包包</a>
</p>
</li>
<li class="even">
<p class="menu_title bggyp"><a href="#" target="_blank">工业品</a></p>
<p class="menu_sort">
<a href="#" target="_blank">女装</a><a href="#" target="_blank">男装</a><a href="#" target="_blank">童装</a><a href="#" target="_blank">包包</a>
</p>
</li>
<li class="odd">
<p class="menu_title bgxqt"><a href="#" target="_blank">新奇特</a></p>
<p class="menu_sort">
<a href="#" target="_blank">女装</a><a href="#" target="_blank">男装</a><a href="#" target="_blank">童装</a><a href="#" target="_blank">包包</a><br/>
<a href="#" target="_blank">鞋</a><a href="#" target="_blank">饰品</a>
</p>
</li>
</ul>

<div class="menu_box hide">
<div class="menu_cont hide">

<div class="menu_cont01">
<span class="menu_title_video">项目视频</span>
<div class="menu_video">
<ul>
<li><a href="#" target="_blank"><img src="images/ad/home_53.gif" /></a></li>
<li><a href="#" target="_blank"><img src="images/ad/home_53.gif" /></a></li>
<li><a href="#" target="_blank"><img src="images/ad/home_53.gif" /></a></li>
<li><a href="#" target="_blank"><img src="images/ad/home_53.gif" /></a></li>
<li><a href="#" target="_blank"><img src="images/ad/home_53.gif" /></a></li>
</ul>
</div>
<div class="scroll_menu">
<span class="prev_menu" href="#"></span>
<span class="next_menu" href="#"></span>
<div class="roolbox_menu">
<div class="scroll_list_menu">
<ul>
<li>
<p class="ad_logo ad_fs01">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名" /></a>
</p>
<p class="ad_logo">
<span class="ad_fs02">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名" /></a>
</span>
<span class="ad_fs03">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名" /></a>
</span>

</p>
<p class="ad_logo ad_fs04">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</p>
<p class="ad_logo">
<span class="ad_fs02">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</span>
<span class="ad_fs03">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</span>

</p>
<p class="ad_logo">
<span class="ad_fs05">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</span>
<span class="ad_fs06">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</span>

</p>
</li>
<li>
<p class="ad_logo ad_fs01">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名" /></a>
</p>
<p class="ad_logo">
<span class="ad_fs02">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名" /></a>
</span>
<span class="ad_fs03">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名" /></a>
</span>

</p>
<p class="ad_logo ad_fs04">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</p>
<p class="ad_logo">
<span class="ad_fs02">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</span>
<span class="ad_fs03">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</span>

</p>
<p class="ad_logo">
<span class="ad_fs05">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</span>
<span class="ad_fs06">
<a href="#" target="_blank"><img src="images/ad/home_88.jpg" alt="项目名"/></a>
</span>

</p>
</li>
</ul>
</div>
</div>
</div>

<div class="menupic_fsxb"><img src="images/pic_fsxb.png" /></div>
</div>



</div>
<div class="menu_cont hide">2</div>
<div class="menu_cont hide">3</div>
<div class="menu_cont hide">4</div>
<div class="menu_cont hide">5</div>
<div class="menu_cont hide">6</div>
<div class="menu_cont hide">7</div>
<div class="menu_cont hide">8</div>
</div>
</div>
<!--中间项目展示-->

$(".menu_list li").mouseenter(function(){
$(".menu_box").show();
var nav_index = $(".menu_list li").index(this);
$(".menu_cont").eq(nav_index).show()//滑动菜单对应当前内容
.siblings().hide();
}) ;
$(".menu").mouseleave(function(){

$(".menu_box").hide();
}) ;