HTML5文件拖拽上传记录

 JS文件：
 var FileName = "";
 var FileStr = "";
 (function () {
     function $id(id) {
         return document.getElementById(id);
     }
     function Output(msg) {
         var m = $id("filedrag");
         m.innerHTML = msg + m.innerHTML;
     }
     function FileDragHover(e) {
         e.stopPropagation();
         e.preventDefault();
         e.target.className = (e.type == "dragover" ? "hover" : "");
     }
     function FileSelectHandler(e) {
         FileDragHover(e);
         var files = e.target.files || e.dataTransfer.files;
         for (var i = , f; f = files[i]; i++) {
             ParseFile(f);
             UploadFile(f); //暂时注释
         }
     }
     function ParseFile(file) {

         //pic类型
         if (file.type.indexOf("image") == ) {
             var reader = new FileReader();
             reader.onload = function (e) {
                 Output(
                     "<p><strong>" + file.name + ":</strong><br />" +
                     '<img src="' + e.target.result + '" /></p>'
                 );
                 FileStr=e.target.result;
             }
             reader.readAsDataURL(file);
         }
         //文本类型处理
         if (file.type.indexOf("text") == ) {
             var reader = new FileReader();
             reader.onload = function (e) {
                 Output(
                     "<p><strong>" + file.name + ":</strong></p><pre>" +
                     e.target.result.replace(/</g, "&lt;").replace(/>/g, "&gt;") +
                     "</pre>"
                 );
             }
             reader.readAsText(file);
         }
     }
     function uploadProgress(evt) {
         if (evt.lengthComputable) {
             var percentComplete = Math.round(evt.loaded *  / evt.total);
             document.getElementById('progressNumber').innerHTML = percentComplete.toString() + '%';
         }
         else {
             document.getElementById('progressNumber').innerHTML = '';
         }
     }
     function UploadFile(file) {
         $id("filedrag").innerHTML = ""; //清空当前fileDrg的信息
         if (location.host.indexOf("sitepointstatic") >= ) return
         var xhr = new XMLHttpRequest();
         if (xhr.upload && file.size <= $id("sizebyte").value && file.type == "image/jpeg") {
             var o = $id("progress");
             var progress = o.appendChild(document.createElement("p"));
 //            progress.appendChild(document.createTextNode("名称： " + file.name));
 //                        xhr.upload.addEventListener("progress", function (e) {
 //                            var pc = parseInt(100 - (e.loaded / e.total * 100));
 //                            progress.style.backgroundPosition = pc + "% 0";
 //                        }, true);
             xhr.onreadystatechange = function (e) {
                 alert(xhr.readyState);
                 if (xhr.readyState == ) {
                     progress.className = (xhr.status ==  ? "success" : "failure");
                 }
             };
             var files = file.name;
             FileName=file.name;
         }
     }
     $("#btnUpload").click(function () {
                 if ($("#fileselect").val() == "") {
                  if(FileStr==""){
                     alert("请选择一个图片文件，再点击上传。");
                     return;
                     }else{
                         $.post(
                          "SaveServer.ashx",
                          {FileStr:FileStr},
                           function(data){
                             alert("成功");
                              $("#fileselect").val("");
                           });
                     }
                 }else{
                 $.post(
                          "SaveServer.ashx",
                          {FileStr:FileStr},
                           function(data){
                             alert("成功");
                              $("#fileselect").val("");

                           });
                 }

             });
     function Init() {
         var hh = this;
         var fileselect = $id("fileselect"),
             filedrag = $id("filedrag")/
             fileselect.addEventListener("change", FileSelectHandler, false);

         var xhr = new XMLHttpRequest();
         if (xhr.upload) {

             filedrag.addEventListener("progress", uploadProgress, false);
             filedrag.addEventListener("dragover", FileDragHover, false); //如果鼠标移动但停留在同一个控件中，则引发DragOver事件
             filedrag.addEventListener("dragleave", FileDragHover, false); //如果用户移出一个窗口，则引发DragLeave事件
             filedrag.addEventListener("drop", FileSelectHandler, false); //完成拖放操作
             filedrag.style.display = "block";
             upButton.style.display = "block";
         } 

     }
     if (window.File && window.FileList && window.FileReader) {
         Init();
     } else {
         upButton.style.display = "block";
         alert("您的浏览器不支持File API");
     }
 })();

后台接受页面：
context.Response.ContentType = "text/plain";
            string[] aa = context.Request.Form["FileStr"].Split(',');
            MemoryStream ms = new MemoryStream(Convert.FromBase64String(aa[]));
            Bitmap b = new Bitmap(ms);
            string serverPath = System.Web.HttpContext.Current.Server.MapPath("~");

            string toFilePath = Path.Combine(serverPath, @"images\headimg\");
            string pach = toFilePath + GetImageName() + ".jpg";
            b.Save(pach);
            context.Response.Write("yes");
            context.Response.End();