<div class="tab">
<li class="selected" >1</li>
<li class="hover">2</li>
<li class="hover">3</li>
</div>
<div class="tab_box">
<div class="newslist">第一个</div>
<div class="newslist">第二个</div>
<div class="newslist">第三个</div>
</div>

$().PPXTabs({ nav:'.tab li',nav_txt:'.tab_box div',selectedClass:'selected',hoverClass:'hover'});

/* ================================================================
* Copyright 2009 PPX
* 邮箱: Mr.cuix@Gmail.com
* 原始版本作者:PPX 创建时间:2010-2-8 10:20
* ================================================================
* 参数说明
* <param name="nav">导航列</param>
* <param name="nav_txt">导航内容</param>
* <param name="selectedClass">选中时的样式</param>
* <param name="hoverClass">经过时的样式</param>
*
* 默认为
* $().PPXTabs({
nav:'.news_title1 li',
nav_txt:'.news_list_box div',
selectedClass:'tab_1_A',
hoverClass:'tab_1_B'
});
===================================
Demo
-----
<div class="tab">
<li class="selected" >1</li>
<li class="hover">2</li>
<li class="hover">3</li>
</div>
<div class="tab_box">
<div class="newslist">第一个</div>
<div class="newslist">第二个</div>
<div class="newslist">第三个</div>
</div>
===================================
css
-----
$().PPXTabs({ nav:'.tab li',nav_txt:'.tab_box div',selectedClass:'selected',hoverClass:'hover'});
*/

$.fn.PPXTabs=function(options){
//默认配置
var settings={
nav:'.news_title1 li',
nav_txt:'.news_list_box div',
selectedClass:'tab_1_A',
hoverClass:'tab_1_B'
};
//主函数
$(function(){
var tab_menu_li = $(settings.nav);
$(settings.nav_txt+':gt(0)').hide();

tab_menu_li.hover(function(){
//鼠标移入
$(this).removeClass(settings.hoverClass);
$(this).siblings().find("."+settings.selectedClass).removeClass(settings.selectedClass);
$(this).siblings("li").addClass(settings.hoverClass);
$(this).addClass(settings.selectedClass);
var index = tab_menu_li.index(this);
$(settings.nav_txt).eq(index).show().siblings().hide();
},function(){
//鼠标移出
$(this).removeClass(settings.selectedClass);
$(this).siblings().find("."+settings.selectedClass).removeClass(settings.selectedClass);
$(this).siblings("li").addClass(settings.hoverClass);
$(this).addClass(settings.selectedClass);

});

});
if(options){
$.extend(settings,options);
}


};