<div id="menu">

<a href="{siteurl($siteid)}"><div class="list" style="float:left">首页</div></a>

{pc:content action="category" catid="0" num="5" siteid="$siteid" order="listorder ASC"}

   {loop $data $r}

       <div class="caidan">

       <a href="{$r[url]}"><div class="list">{$r[catname]}</div></a>

       <div class="erji">

           {pc:content action="category" catid="$r[catid]" num="5" siteid="$siteid" order="listorder ASC" return="data1"}               {loop $data1 $v}

            　　　　<a href="{$v[url]}"><div class="erjicaidan">{$v[catname]}</div></a>

              {/loop}

           {/pc}

       </div>

       </div>

   {/loop}
{/pc}

//js代码:

$(document).ready(function(e) {

    $(".caidan").mouseenter(function(){

        $(".erji").css("display","none");

        $(this).children(".erji").css("display","block");

    })

    $(".caidan").mouseleave(function(){

        $(this).children(".erji").css("display","none");

        })

});

<div id="tupian">

 　　{pc:content  action="position" posid="18"  order="listorder DESC" thumb="1" num="5"}

        {loop $data $r}

        <a href="{$r['url']}"><img class="lunbo" src="{thumb($r['thumb'],1200,300)}" width="1200" height="300" style="display:block" /></a>

        {/loop}

 　　{/pc}

</div>

//jquery代码
var n=1; //当前要显示的图片索引

function ShowNow()

{

    var img = $(".lunbo");

    img.css("display","none");

    img.eq(n).css("display","block");

    if(n>=img.length-1)

    {

        n=0;

    }

    else

    {

        n++;

    }

}

window.setInterval("ShowNow()",1000);