jQuery插件uploadify实现ajax效果的图片上传

<script type="text/javascript" src="../js/jquery-1.4.2.min.js"></script>
<script src="../Plugin/swfobject.js" type="text/javascript"></script>
<script src="../Plugin/jquery.uploadify.v2.1.4.min.js" type="text/javascript"></script>

<tr>
<th scope="row">图 片：</th>
<td>
　　<div style="float:left;width:125px;height:35px;">
 　　<input type="file" name="uploadify" id="uploadify" /> <%--上传时的进度条--%>
 </div>
 <div id="fileQueue" style="float:left;height:35px;"></div>
 <div style="float:left;height:35px;">
 　　<a href="javascript:$('#uploadify').uploadifyUpload()" class="btn-lit"><span>上传</span></a>
  <a href="javascript:$('#uploadify').uploadifyClearQueue()" class="btn-lit"><span>取消上传</span></a>
 </div>
</td>
</tr>
<tr>
  <th scope="row">&nbsp;</th>
  <td><asp:Image ID="pic" runat="server" /></td>　　<%--成功上传生成图片预览功能--%>
</tr>

//uploadify插件的自定义设置
$(document).ready(function () {
 $("#uploadify").uploadify({
  'uploader': '../Plugin/uploadify.swf',
  'script': 'UploadImg.ashx',
  'cancelImg': '../Plugin/cancel.png',
  'folder': '../upload',
  'buttonText': 'SELECT Pic',
  'fileExt': '*.jpg;*.gif,*.png',     //允许上传的文件格式为*.jpg,*.gif,*.png
  'fileDesc': 'Web Image Files(.JPG,.GIF,.PNG)', //过滤掉除了*.jpg,*.gif,*.png的文件
  'queueID': 'fileQueue',
  'sizeLimit': '2048000',       //最大允许的文件大小为2M
  'auto': false,         //需要手动的提交申请
  'multi': false,         //一次只允许上传一张图片
  'onCancel': funCancel,       //当用户取消上传时
  'onComplete': funComplete,      //完成上传任务
  'OnError': funError        //上传发生错误时
 });
});

//用户取消函数
function funCancel(event, ID, fileObj, data) {
 jBox.tip('您取消了' + fileObj.name + '操作', 'info');
 return;
}

//图片上传发生的事件
function funComplete(event, ID, fileObj, response, data) {
 //$("#pic").html('<img id="pic" runat="server" src=../upload/' + response + '.jpg style="width:300;height:200px;"/>');
 if (response == 0) {
  jBox.tip('图片' + fileObj.name + '操作失败', 'info');
  return;
 }
 $("#pic").attr("src", "../upload/" + response).height(200).width(300);
 jBox.tip('图片' + fileObj.name + '操作成功', 'info');
 return;
}

//上传发生错误时。
function funError(event, ID, fileObj, errorObj) {
 jBox.tip(errorObj.info);
 return;
}

context.Response.ContentType = "text/plain";
context.Response.Charset = "utf-8";

HttpPostedFile file = context.Request.Files["Filedata"];
string uploadPath = HttpContext.Current.Server.MapPath(@context.Request["folder"]) + "\\";

if (file != null)
{
 //if (File.Exists(uploadPath + file.FileName))
 //{
 // context.Response.Write("3");   //文件已经存在
 // return;
 //}

 string[] fn = file.FileName.Split('.');
 string ext = fn[fn.Length - 1];
 string filename = DateTime.Now.ToString("yyyyMMddhhmmss")+"."+ext;
 if (!Directory.Exists(uploadPath))
 {
  Directory.CreateDirectory(uploadPath);
 }
 file.SaveAs(uploadPath + filename);
 //下面这句代码缺少的话，上传成功后上传队列的显示不会自动消失
 context.Session[context.Session["userName"].ToString()] = filename;
  
 context.Response.Write(filename);
}
else
{
 context.Response.Write("0");
}