图片轮播

转自 http://www.5icool.org/demo/2012/a00552/
 
<!doctype html>
<meta charset="utf-8"/>
<style type="text/css">
.clearfix:after {content: "."; display: block; height: 0; clear: both; visibility: hidden;}
.clearfix {zoom:1;}
ul,li {list-style:none;}
img {border:0;}
.wrapper {800px; margin:0 auto; }
/* qqshop focus */
#focus {800px; height:330px; overflow:hidden; position:relative;margin:0;padding:0;}
#focus ul {height:330px; position:absolute;margin:0;padding:0;}
#focus ul li {float:left; 800px; height:330px; overflow:hidden; position:relative; background:#000;margin:0;padding:0;}
#focus ul li div {position:absolute; overflow:hidden;}
#focus .btnBg {position:absolute; 800px; height:20px; left:0; bottom:0; background:#000;}
#focus .btn {position:absolute; 780px; height:10px; padding:5px 10px; right:0; bottom:0; text-align:right;}
#focus .btn span {display:inline-block; _display:inline; _zoom:1; 25px; height:10px; _font-size:0; margin-left:5px; cursor:pointer; background:#fff;}
#focus .btn span.on {background:#fff;}
#focus .preNext {45px; height:100px; position:absolute; top:90px; background:url(img/sprite.png) no-repeat 0 0; cursor:pointer;}
#focus .pre {left:0;}
#focus .next {right:0; background-position:right top;}

</style>
<script src="jquery-1.5.2.min.js" type="text/javascript"></script>
<script type="text/javascript">
    $(function () {
        var sWidth = $("#focus").width(); //获取焦点图的宽度（显示面积）
        var len = $("#focus ul li").length; //获取焦点图个数
        var index = 0;
        var picTimer;

        //以下代码添加数字按钮和按钮后的半透明条，还有上一页、下一页两个按钮
        var btn = "<div class='btnBg'></div><div class='btn'>";
        for (var i = 0; i < len; i++) {
            btn += "<span></span>";
        }
        btn += "</div><div class='preNext pre'></div><div class='preNext next'></div>";
        $("#focus").append(btn);
        $("#focus .btnBg").css("opacity", 0.5);

        //为小按钮添加鼠标滑入事件，以显示相应的内容
        $("#focus .btn span").css("opacity", 0.4).mouseenter(function () {
            index = $("#focus .btn span").index(this);
            showPics(index);
        }).eq(0).trigger("mouseenter");
       
        //上一页、下一页按钮透明度处理
        $("#focus .preNext").css("opacity", 0.2).hover(function () {
            $(this).stop(true, false).animate({ "opacity": "0.5" }, 300);
        }, function () {
            $(this).stop(true, false).animate({ "opacity": "0.2" }, 300);
        });
        
        //上一页按钮
        $("#focus .pre").click(function () {
            index -= 1;
            if (index == -1) { index = len - 1; }
            showPics(index);
        });

        //下一页按钮
        $("#focus .next").click(function () {
            index += 1;
            if (index == len) { index = 0; }
            showPics(index);
        });
        
        //本例为左右滚动，即所有li元素都是在同一排向左浮动，所以这里需要计算出外围ul元素的宽度
        $("#focus ul").css("width", sWidth * (len));

        //鼠标滑上焦点图时停止自动播放，滑出时开始自动播放
        $("#focus").hover(function () {
            clearInterval(picTimer);
        }, function () {
            picTimer = setInterval(function () {
                showPics(index);
                index++;
                if (index == len) { index = 0; }
            }, 4000); //此4000代表自动播放的间隔，单位：毫秒
        }).trigger("mouseleave");

        //显示图片函数，根据接收的index值显示相应的内容
        function showPics(index) { //普通切换
            var nowLeft = -index * sWidth; //根据index值计算ul元素的left值
            $("#focus ul").stop(true, false).animate({ "left": nowLeft }, 300); //通过animate()调整ul元素滚动到计算出的position
            //$("#focus .btn span").removeClass("on").eq(index).addClass("on"); //为当前的按钮切换到选中的效果
            $("#focus .btn span").stop(true, false).animate({ "opacity": "0.4" }, 300).eq(index).stop(true, false).animate({ "opacity": "1" }, 300); //为当前的按钮切换到选中的效果
        }
    });

</script>
<div class="wrappers">
    
	<div id="focus">
		<ul>
			<li><a href="http://www.baidu.com/"><img src="1.jpg" alt="QQ商城焦点图效果下载" /></a></li>
			<li><a href="http://www.google.com"><img src="2.jpg" alt="QQ商城焦点图效果教程" /></a></li>

		</ul>
	</div>

</div><!-- wrapper end -->