简单的Jquery焦点图切换效果

利用Jquery,优雅的实现焦点图切换
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>jQuery原始左右滚动幻灯片(方便扩展)代码效果</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>
</head>
<body>
<!--代码部分begin-->
<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个]</li>
                <li index="1" style="background:#ff0">[第2个]</li>
                <li index="2" style="background:#f0f">[第3个]</li>
                <li index="3" style="background:#999">[第4个]</li>
                <li index="4" style="background:#666">[第5个]</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 src="http://www.lanrenzhijia.com/ajaxjs/1.4.4/jquery-1.4.4.min.js"></script>
<script>
$(function() {
    $(".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")
    }
    $(".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()
        })
    });
    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>
<!--代码部分end-->
</body>
</html>
摘自：http://demo.lanrenzhijia.com/2015/banner0325/
demo :http://demo.lanrenzhijia.com/2015/banner0325/