点击图片显示放大的图片，并悬浮于窗体之上

<a  href='javascript:void(0);' onclick='picBig();'>

                                <img src="（图片地址）"> style="width: 200px;height: 200px"></a>

                                <!--为要放大的图片设置超链接（点击显示大图）-->

<div id="divCenter" align="center"

                                   style="position: absolute; display: none;  width: 100%; height: 1                                        00%;   position:fixed;z-index:25;">

                                        <img

                                                src="<%=request.getContextPath()%>/showImage?imageId=<%=bill.getF_FILE_ID()%>" style="width:70%;height: 80%"/>

                                                <div style="margin-top: 30px;"><a href="javascript:void(0);" onclick="picClose();" class="close_photo">关闭</a></div>

                                </div>

          <!--要显示的大图，把该div放置到要显示的地方。并把display设置为none使之隐藏-->

通过js使得原来隐藏的div显示出来

<script>

function picBig() {

                var v = document.getElementById('divCenter');

                v.style.display = "block";

              

            }

            function picClose() {

                var v = document.getElementById('divCenter');

                v.style.display = "none";

            }

</script>