动态添加input标签

<style type="text/css">
        .delete_attach
        {
            padding-left: 18px;
            background: url(../image/delete.png) no-repeat left top;
            margin-left: 7px;
            90px;
            color: #002f76;
        }
        .add_attach
        {
            padding-left: 22px;
            background: url(../image/add.png) no-repeat left center;
            90px;
            color: #002f76;
        }
    </style>
    <script type="text/javascript">
        var MAXFILES = 10;        //文件计数器
        var fileCount = 0;
        function addAttach(noAlert) {
            if (fileCount >= MAXFILES && !noAlert) { alert("最多只能添加" + MAXFILES + "个附件！"); return; }
            var fileSectionDiv = document.getElementById("files");
            var fileItemDiv = document.createElement("div");
            fileCount++;
            var content = "<input type='file' onchange='return addAttach(true);' id=='fileUpload'" + fileCount + " name='fileUpload'" + fileCount + ">&nbsp;<a href='#' onclick='return delAttach("" + fileCount + "")' class='delete_attach' >移除附件</a>";
            fileItemDiv.id = "fileItemDiv" + fileCount;
            fileItemDiv.innerHTML = content;
            fileSectionDiv.appendChild(fileItemDiv);
            return false;
        }

        function delAttach(fileIndex) {
            var fileSectionDiv = document.getElementById("files");
            var fileItemDiv = document.getElementById("fileItemDiv" + fileIndex);
            fileSectionDiv.removeChild(fileItemDiv);
            fileCount--;
            return false;
        }   
    </script>

<form id="form1" runat="server" method="post" enctype="multipart/form-data">

<a id="addAttach_a" onclick="return addAttach(false);" href="#" class="add_attach">添加附件</a>
                            <div id="files" runat="server">
                            </div>

</form>

string file = "Files";
            string path = Server.MapPath(file);
            if (!System.IO.Directory.Exists(path))//判断文件夹是否已经存在
            {
                System.IO.Directory.CreateDirectory(path);//创建文件夹
            }
            for (int index = 0; index < Request.Files.Count; index++)
            {
                if (!string.IsNullOrEmpty(Request.Files[index].FileName))
                {
                    string NewName = DateTime.Now.ToString("yyyyMMddHHmmss") + rd.Next(10000, 99999);
                    string Extension = Path.GetExtension(Request.Files[index].FileName);
                    Request.Files[index].SaveAs(Path.Combine(path, NewName + Extension));
                    details.Add(new AdvertiseDetail
                    {
                        Id = Utils.CreateGUID(),
                        FileName = file,
                        NewName = NewName + Extension,
                        OldName = System.IO.Path.GetFileName(Request.Files[index].FileName),
                        CreatedByID = "1001",
                        CreatedDate = DateTime.Now,
                        LastModifiedByID = "1001",
                        LastModifiedDate = DateTime.Now
                    });
                }
            } 

 学习视频分享交流群