<div id="jnBrandList">

                            <ul>

                                <li>

                                    <a href="###1" class="JS_live"><img alt="耐克" src="data:images/upload/20120217.jpg" /></a>

                                    <span><a href="###1">耐克</a></span>

                                </li>

                                <li>

                                    <a href="###2" class="JS_live"><img alt="阿迪达斯" src="data:images/upload/20120218.jpg" /></a>

                                    <span><a href="###2">阿迪达斯</a></span>

                                </li>

                                <li>

                                    <a href="###3" class="JS_live"><img alt="李宁" src="data:images/upload/20120219.png" /></a>

                                    <span><a href="###3">李宁</a></span>

                                </li>

                                <li>

                                    <a href="###4" class="JS_live"><img alt="安踏" src="data:images/upload/20120220.png" /></a>

                                    <span><a href="###4">安踏</a></span>

                                </li>

                                <li>

                                    <a href="###1" class="JS_live"><img alt="耐克" src="data:images/upload/20120217.jpg" /></a>

                                    <span><a href="###1">耐克</a></span>

                                </li>

                                <li>

                                    <a href="###2" class="JS_live"><img alt="阿迪达斯" src="data:images/upload/20120218.jpg" /></a>

                                    <span><a href="###2">阿迪达斯</a></span>

                                </li>

                                <li>

                                    <a href="###3" class="JS_live"><img alt="李宁" src="data:images/upload/20120219.png" /></a>

                                    <span><a href="###3">李宁</a></span>

                                </li>

                                <li>

                                    <a href="###4" class="JS_live"><img alt="安踏" src="data:images/upload/20120220.png" /></a>

                                    <span><a href="###4">安踏</a></span>

                                </li>

                                <li>

                                    <a href="###1" class="JS_live"><img alt="耐克" src="data:images/upload/20120217.jpg" /></a>

                                    <span><a href="###1">耐克</a></span>

                                </li>

                                <li>

                                    <a href="###2" class="JS_live"><img alt="阿迪达斯" src="data:images/upload/20120218.jpg" /></a>

                                    <span><a href="###2">阿迪达斯</a></span>

                                </li>

                                <li>

                                    <a href="###3" class="JS_live"><img alt="李宁" src="data:images/upload/20120219.png" /></a>

                                    <span><a href="###3">李宁</a></span>

                                </li>

                                <li>

                                    <a href="###4" class="JS_live"><img alt="安踏" src="data:images/upload/20120220.png" /></a>

                                    <span><a href="###4">安踏</a></span>

                                </li>

                                <li>

                                    <a href="###1" class="JS_live"><img alt="耐克" src="data:images/upload/2014050201.jpg" /></a>

                                    <span><a href="###1">书1</a></span>

                                </li>

                                <li>

                                    <a href="###2" class="JS_live"><img alt="阿迪达斯" src="data:images/upload/2014050202.jpg" /></a>

                                    <span><a href="###2">书2</a></span>

                                </li>

                                <li>

                                    <a href="###3" class="JS_live"><img alt="李宁" src="data:images/upload/2014050203.jpg" /></a>

                                    <span><a href="###3">书3</a></span>

                                </li>

                                <li>

                                    <a href="###4" class="JS_live"><img alt="安踏" src="data:images/upload/2014050204.jpg" /></a>

                                    <span><a href="###4">书4</a></span>

                                </li>

                            </ul>

                        </div>

/* imgHover */

.imageMask{

    background-color:#ffffff;

    filter:alpha(opacity=0);

    opacity:;

    cursor: pointer;

}

.imageOver{

    background:url(../images/zoom.gif) no-repeat 50% 50%;

    filter:alpha(opacity=60);

    opacity: 0.6;

}

$(function () {

    $("#jnBrandList li").each(function (index) {

        var $img = $(this).find("img");

        var imgWidth = $img.width();

        var imgHeight = $img.height();

        //为每个图片链接上添加遮罩层，透明度为0

        var spanHtml = '<span style="position:absolute;top:0;left:5px;width:' + imgWidth + 'px;height:' + imgHeight + 'px;" class="imageMask"></span>'; ;

        $(spanHtml).appendTo(this);

    });

    //遮罩层切换样式

    $("#jnBrandList").delegate(".imageMask", "hover", function () {

        $(this).toggleClass("imageOver");

    });

    /*live函数是为页面加载完后动态加载的元素绑定事件。

    $("#jnBrandList").find(".imageMask").live("hover", function(){

    $(this).toggleClass("imageOver");

    });

    */

});