一个实用的图片切换支持点击切换和自动轮播

<div class="scroll_div">
<ul class="pic">
<li><img src="img/pic_1.jpg" /></li>
<li><img src="img/pic_2.jpg" /></li>
<li><img src="img/pic_3.jpg" /></li>
<li><img src="img/pic_4.jpg" /></li>
<li><img src="img/pic_5.jpg" /></li>
</ul>
<ul class="btn">
<li>项目一</li>
<li>项目二</li>
<li>项目三</li>
<li>项目四</li>
<li>项目五</li>
</ul>
</div>

.scroll_div{width:1000px; height:370px; margin:0 auto; padding:10px;}
.scroll_div .pic{width:820px; height:370px; overflow:hidden; position:relative; float:left;}
.scroll_div .pic li{width:820px; height:370px; position:absolute; top:0; left:0; display:none;}
.scroll_div .btn{float:right; width:173px;}
.scroll_div .btn li{width:173px; height:66px; display:block; float:left; text-align:center; color:#fff; font:18px/100% "微软雅黑"; font-weight:bold; background:#008dd8; margin-bottom:10px; line-height:66px; cursor:pointer;}
.scroll_div .btn li.on{background:#d73737;}

li {list-style:none;}

$(function(){
var listLen = $(".pic li").length, i=0,setInter,speen = 3000;
/*图片轮播*/
$(".btn li:last").css({"margin":"0px 0px 0px 0px"});
$(".btn li:first").addClass("on");
$(".pic li:first").show();

$(".btn li").each(function(index,element){
$(element).click(function(){
i = index;
$(this).addClass("on").siblings().removeClass("on");
$(".pic li").eq(index).animate({opacity:"show"},300).siblings().animate({opacity:"hide"},300);
})
$(element).hover(function(){
clearInterval(setInter);
},function(){
outPlay();
});
})


out_fun = function(){
if(i < listLen){i++;}else{i=0;};
$(".btn li").eq(i).addClass("on").siblings().removeClass("on");
$(".pic li").eq(i).animate({opacity:"show"},300).siblings().animate({opacity:"hide"},300);
}

outPlay = function(){
setInter = setInterval("out_fun()",speen);
}
outPlay();
})