js实现的常用的左侧导航效果

常用的左侧导航效果，JS简单，为提高导航性能而生，各位可以 参考应用。

效果展示：
 
HTML:

<!--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-->

JS：

$(".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(); 
}) ;