jQuery实现友好的轮播图片特效

.gy-slide-scroll {
        position: relative;
        width: 320px;
        height: 200px;
        overflow: hidden;
        left: 50%;
        margin-left: -160px;
    }
    .gy-slide-scroll ul{
        position: absolute;
        left: 0;
        top: 0;
    }
    .gy-slide-btn {
        margin-top: 10px;
        text-align: center;
        padding: 5px 0;
    }
    .gy-slide-btn span,.gy-slide-btn i {
        margin-left: 5px;
        font-style: normal;
        font:12px/1 tahoma,arial,"Hiragino Sans GB",/5b8b/4f53;
        cursor: pointer;
        border: 1px solid #ccc;
        padding: 4px 6px;
    }
    .gy-slide-btn .gy-slide-cur {
        background-color: #999;
        color: #fff;
    }
    .gy-slide-btn .gy-slide-no{
        color: #ccc;
        cursor: default;
    }

<div id="gy-slide">
        <div class="gy-slide-scroll">
            <ul>
                <li><a href="#"><img src="img/n1.jpg" alt=""></a></li>
                <li><a href="#"><img src="img/n2.jpg" alt=""></a></li>
                <li><a href="#"><img src="img/n3.jpg" alt=""></a></li>
                <li><a href="#"><img src="img/n4.jpg" alt=""></a></li>
                <li><a href="#"><img src="img/n5.jpg" alt=""></a></li>
            </ul>
        </div>
        <div class="gy-slide-btn">
            <i class="gy-slide-home">首页</i>
            <i class="gy-slide-prev gy-slide-no">上一页</i>
            <span class="gy-slide-cur">1</span>
            <span>2</span>
            <span>3</span>
            <span>4</span>
            <span>5</span>
            <i class="gy-slide-next">下一页</i>
            <i class="gy-slide-end">尾页</i>
        </div>
    </div>

/*----使用说明
结构必需一致;多次调用时，最外层赋予不同的id或类名即可
*/
/*----参数
@ wrap [String] 外层元素的类名或id
@ auto [Boolean] 不设置默认是不自动播放；设置为true，自动播放
@ speed [Number] 每隔几秒图片切换，默认是4秒
*/
function Gy_slider(opt){
    this.wrap = $(opt.wrap);
    this.scroll = this.wrap.find('.gy-slide-scroll ul');
    this.li = this.scroll.find('li');
    this.btn_num = this.wrap.find('.gy-slide-btn span');
    this.btn_home = this.wrap.find('.gy-slide-home');
    this.btn_end = this.wrap.find('.gy-slide-end');
    this.btn_prev = this.wrap.find('.gy-slide-prev');
    this.btn_next = this.wrap.find('.gy-slide-next');
    this.index = 0; //索引
    this.refer = 0;
    this.ctrl = true;
    this.len = this.li.length;
    this.move_w = this.scroll.parent().width();
    this.auto = opt.auto == true?true:false;
    this.speed = opt.speed || 4;
    this.init();
}
Gy_slider.prototype = {
    imgShow:function(i,callback){
        var _that = this,
            _w = 0;
        switch(true){
            case i<this.refer : _w = - this.move_w;break;
            case i==this.refer : return;break;
            default:_w = this.move_w;
            }
        this.refer = i;
        this.li.eq(i).css({'position':'absolute','left':_w+'px','top':0});
        this.scroll.stop(true,true).animate({'left':-_w+'px'},function(){
            _that.scroll.css({'left':0});
            _that.li.attr('style','').eq(i).css({'position':'absolute','left':0,'top':0});
            if(typeof callback == 'function'){
                callback();
            }
        });
        this.btn_num.removeClass("gy-slide-cur").eq(i).addClass("gy-slide-cur");
    },
    isCtrl:function(n){
        this.btn_prev.add(this.btn_next).removeClass("gy-slide-no");
        if(n==0){
            this.btn_prev.addClass("gy-slide-no");
        }else if(n==(this.len-1)){
            this.btn_next.addClass("gy-slide-no");
        }
    },
    btnClick:function(){
        var _that = this;
        //页码处理
        this.btn_num.click(function(){
            if(_that.btn_num.index($(this))==_that.index) return;
            if(!_that.ctrl) return;
            _that.ctrl = false;
            _that.index = _that.btn_num.index($(this));
            _that.isCtrl(_that.index);
            _that.imgShow(_that.index,function(){
                _that.ctrl = true;
            });
        });
        //首页
        this.btn_home.click(function(){
            _that.index = 0;
            _that.isCtrl(_that.index);
            _that.imgShow(_that.index);
        });
        //尾页
        this.btn_end.click(function(){
            _that.index = _that.len - 1;
            _that.isCtrl(_that.index);
            _that.imgShow(_that.index);
        });
        //上一页
        this.btn_prev.click(function(){
            if($(this).hasClass("gy-slide-no")) return;
            if(!_that.ctrl) return;
            _that.ctrl = false;
            _that.index--;
            _that.isCtrl(_that.index);
            _that.imgShow(_that.index,function(){
                _that.ctrl = true;
            });
        });
        //下一页
        this.btn_next.click(function(){
            if($(this).hasClass("gy-slide-no")) return;
            if(!_that.ctrl) return;
            _that.ctrl = false;
            _that.index++;
            _that.isCtrl(_that.index);
            _that.imgShow(_that.index,function(){
                _that.ctrl = true;
            });
        });

    },
    autoPlay:function(){
        var _that = this;
        if(this.timer) clearInterval(this.timer);
        this.timer = setInterval(function(){
            _that.index++;
            if(_that.index==_that.len){
                _that.index = 0;
            }
            _that.isCtrl(_that.index);
            _that.imgShow(_that.index);
        },this.speed*1000);
    },
    init:function(){   
        var _that = this;       
        this.btnClick();
        if(this.auto){
            this.autoPlay();
            this.wrap.hover(function(){
                clearInterval(_that.timer);
            },function(){
                _that.autoPlay();
            });
        }
    }
}