求各位大神指教，怎么在此基础上添加自动轮播功能？急急急。。。
<!DOCTYPE>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<meta http-equiv="content-language" content="zh-cn" />
<title>jQuery左右滑动切换图片</title>
<style>
*{margin:0px;padding:0px;list-style-type:none;}
.v_out{width:748px;margin:20px auto;overflow:hidden;}
.v_show{width:665px;overflow:hidden;position:relative;height:280px;float:left}
.v_cont{ width:6650px;position:absolute;left:0px;top:0px;}
.v_cont ul{float:left;text-align:center;line-height:50px;}
.v_cont ul li{width:665px;height:250px;background:#f8f8f8;float:left;margin-top:3px;}
/*---圆圈---*/
.v_out_p{position:relative;overflow:visible}
.circle{position:absolute;left: 40px;top: 290px;}
.circle li{width:120px;height:60px;float:left;margin-right:10px;background:#ccc}
.circle .circle-cur{background:#f00}
/*---切换---*/
.prev,.next{float:left;padding:105px 9px 0}
.prev a{ background:#f00;}
.prev .ico_1{ background:url(input_a.gif) no-repeat 0 -3757px;}
.next a{background:#f00 }
.next .ico_2{background:url(input_a.gif) no-repeat right -3757px;}
.prev,.prev a,.next,.next a{width:21px;height:28px; display:block}
</style>
<script type="text/javascript" src="js/jquery-1.4.4.js"></script>
</head>
<body>
<div class="v_out v_out_p">
<div class="prev"><a href="javascript:void(0)"></a></div>
<div class="v_show">
<div class="v_cont">
<ul>
<li index="0" style="background:#f00">[第1讲]</li>
<li index="1" style="background:#ff0">[第2讲]</li>
<li index="2" style="background:#f0f">[第3讲]</li>
<li index="3" style="background:#999">[第4讲]</li>
<li index="4" style="background:#666">[第5讲]</li>
</ul>
</div>
</div>
<div class="next"><a href="javascript:void(0)"></a> </div>
<ul class="circle">
<li class="circle-cur">1</li>
<li>2</li>
<li>3</li>
<li>4</li>
<li>5</li>
</ul>
</div>
<script type="text/javascript">
$(function(){
/*======next======*/
$(".next a").click(function(){ nextscroll() });
function nextscroll(){
var vcon = $(".v_cont ");
var offset = ($(".v_cont li").width())*-1;
vcon.stop().animate({left:offset},"slow",function(){
var firstItem = $(".v_cont ul li").first();
vcon.find("ul").append(firstItem);
$(this).css("left","0px");
circle()
});
};
function circle(){
var currentItem = $(".v_cont ul li").first();
var currentIndex = currentItem.attr("index");
$(".circle li").removeClass("circle-cur");
$(".circle li").eq(currentIndex).addClass("circle-cur");
}
//setInterval(nextscroll,2000)
/*======prev======*/
$(".prev a").click(function(){
var vcon = $(".v_cont ");
var offset = ($(".v_cont li").width()*-1);
var lastItem = $(".v_cont ul li").last();
vcon.find("ul").prepend(lastItem);
vcon.css("left",offset);
vcon.animate({left:"0px"},"slow",function(){
circle()
})
});
/*======btn====circle======*/
var animateEnd = 1;
$(".circle li").click(function(){
if(animateEnd==0){return;}
$(this).addClass("circle-cur").siblings().removeClass("circle-cur");
var nextindex = $(this).index();
var currentindex = $(".v_cont li").first().attr("index");
var curr = $(".v_cont li").first().clone();
if(nextindex > currentindex){
for (var i = 0; i < nextindex - currentindex; i++) {
var firstItem = $(".v_cont li").first();
$(".v_cont ul").append(firstItem);
}
$(".v_cont ul").prepend(curr);
var offset = ($(".v_cont li").width())*-1;
if(animateEnd==1){
animateEnd=0;
$(".v_cont").stop().animate({left:offset},"slow",function(){
$(".v_cont ul li").first().remove();
$(".v_cont").css("left","0px");
animateEnd=1;
});
}
}else{
var curt = $(".v_cont li").last().clone();
for (var i = 0; i < currentindex - nextindex; i++) {
var lastItem = $(".v_cont li").last();
$(".v_cont ul").prepend(lastItem);
}
$(".v_cont ul").append(curt);
var offset = ($(".v_cont li").width())*-1;
$(".v_cont").css("left",offset);
if(animateEnd==1){
animateEnd=0;
$(".v_cont").stop().animate({left:"0px"},"slow",function(){
$(".v_cont ul li").last().remove();
animateEnd=1;
});
}
}
});
})
</script>
</body>
</html>
ppo_YXWU