求解一个兼容问题

<script type="text/javascript" language="javascript">      

        $(function () {

            $(".ab2_5 > ul > div > li > div >img ").each(function (i, n) {

                $(n).attr("onmouseover", "fnSetImgsrc1('" + $(n).attr("dimg") + "')");

            });

         

        });



        function fnSetImgsrc1(srcstr) {

            $("#imgmain").attr("src", srcstr);

        }    

    </script>

代码：

<div class="ab2_2">
                            <div class="ab2_3">
                                <div class="hidden">                               
                                        <img style="width: 560px; height: 310px;" src='<%=firstimg%>' id="imgmain" />
                                </div>
                            </div>
                            <div class="ab2_4">
                                <div class="ab2_5" id="move"  style="overflow:hidden">
                                    <ul>
                                        <div id="seconde" style="width: 500px; height:2000px">
                                            <asp:Repeater&n