鼠标经过更换内容

<script>
$(function(){
window.onload = function()
{
var $li = $('#tab li');
var $ul = $('#content ul');

$li.mouseover(function(){
var $this = $(this);
var $t = $this.index();
$li.removeClass();
$this.addClass('current');
$ul.css('display','none');
$ul.eq($t).css('display','block');
})
}
});
</script>

<div class="qdydsy_nr01_nk_xwzx_top">
<div class="qdydsy_nr01_nk_xwzx_top_left">
<ul id="tab">
<li class="current"><a href="#">新闻中心</a></li>
<li><a href="#">加盟问答</a></li>
</ul>
</div>
<div class="qdydsy_nr01_nk_xwzx_top_right"><a href="{:getcategory(4,'url')}">更多</a></div>
</div>
<div id="content">
<div class="qdydsy_nr01_nk_xwzx_zhong" style="display: block" >
<!-----新闻中心的样式开始------>
<ul class="xwzxys" style="display: block">
<content action="lists" num="7" order="id desc" catid="14">
<volist name="data" id="vo">
<li>
<span class="xwzx_left"><a href="{$vo.url}">{$vo.title|str_cut=###,21}</a></span>
<span class="xwzx_right">{$vo.updatetime|date="m-d",###}</span>
</li>
</volist>
</content>
</ul>
<!-----新闻中心的样式结束------>
<!-----加盟问答的样式开始------>
<ul class="jmwdys" style="display: none">
<content action="lists" num="4" order="id DESC" catid="15">
<volist name="data" id="vo">
<li>
<p><a href="{$vo.url}">问：{$vo.title|str_cut=###,22}</a></p>
<p>答：{$vo.description|str_cut=###,22}</p>
</li>
</volist>
</content>
</ul>
<!-----加盟问答的样式结束------>
</div>
</div>