JQ主页图片划动切换效果

.wrapper { 726px; float: left; }

#jiao_dian { 980px; *height: 292px; margin-top: 10px; margin-right: auto; margin-bottom: 0; margin-left: auto; }

#focus { 726px; height: 280px; overflow: hidden; position: relative; }
#focus ul { height: 380px; position: absolute; }
#focus ul li { float: left; 726px; height: 280px; overflow: hidden; position: relative; background: #000; }

#focus .preNext { 45px; height: 100px; position: absolute; top: 90px; background: url(../images/sprite.png) no-repeat 0 0; cursor: pointer; }
#focus .pre { left: 0; }
#focus .next { right: 0; background-position: right top; }

#focus .btnBg { position: absolute; 726px; height: 20px; left: 0; bottom: 0; background: #000; }
#focus .btn { position: absolute; 726px; 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; }

<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 id="jiao_dian">  
    <div class="wrapper">
      <div id="focus">
        <ul>
            <li><a target="_blank" href="#" title="登录""><img src="images/jiao_1.png"/></a></li>
            <li><a target="_blank" href="#"><img src="images/jiao_1.png"/></a></li>
            <li><a target="_blank" href="#"><img src="images/jiao_1.png"/></a></li>
            <li><a target="_blank" href="#"><img src="images/jiao_1.png"/></a></li>
            <li><a target="_blank" href="#"><img src="images/jiao_1.png"/></a></li>
        </ul>
<!--      <div class="btnBg" style="opacity: 0.5;"></div><div class="btn"><span style="opacity: 1;"></span><span style="opacity: 0.4;"></span><span style="opacity: 0.4;"></span><span style="opacity: 0.4;"></span><span style="opacity: 0.4;"></span></div><div class="preNext pre" style="opacity: 0.2;"></div><div class="preNext next" style="opacity: 0.2;"></div>
-->     
 </div>
    </div>
    
    <div class="an_niu">
        <ul>
            <li><a href="DistanceEducationWeb/PersonRegister.aspx"><img src="images/an_1.png"/></a></li>
            <li><a href="/DistanceEducationWeb/UnitRegister.aspx"><img src="images/an_2.png"/></a></li>
            <li><a href="DistanceEducationWeb/PersonHome.aspx"><img src="images/an_3.png"/></a></li>
            <li><a href="DistanceEducationWeb/payment.aspx"><img src="images/an_4.png"/></a></li>
        </ul>
    </div> 
    <div class="clear"></div>   
  </div>