不是原创，但有必要记录一下，免得每次都找的很辛苦

html

js

function fileSelected() {

var file = document.getElementById('fileToUpload').files[0];

if (file) {

var fileSize = 0;

if (file.size > 1024 * 1024)

fileSize = (Math.round(file.size * 100 / (1024 * 1024)) / 100).toString() + 'MB';

else

fileSize = (Math.round(file.size * 100 / 1024) / 100).toString() + 'KB';

document.getElementById('fileName').innerHTML = 'Name: ' + file.name;

document.getElementById('fileSize').innerHTML = 'Size: ' + fileSize;

document.getElementById('fileType').innerHTML = 'Type: ' + file.type;

}

}

function uploadFile() {

var fd = new FormData();

fd.append("fileToUpload", document.getElementById('fileToUpload').files[0]);

var xhr = new XMLHttpRequest();

xhr.upload.addEventListener("progress", uploadProgress, false);

xhr.addEventListener("load", uploadComplete, false);

xhr.addEventListener("error", uploadFailed, false);

xhr.addEventListener("abort", uploadCanceled, false);

xhr.open("POST", "/Home/ToLead");

//xhr.open("POST", "UploadMinimal.aspx");

xhr.send(fd);

}

function uploadProgress(evt) {

if (evt.lengthComputable) {

var percentComplete = Math.round(evt.loaded * 100 / evt.total);

document.getElementById('progressNumber').innerHTML = percentComplete.toString() + '%';

}

else {

document.getElementById('progressNumber').innerHTML = 'unable to compute';

}

}

function uploadComplete(evt) {

/* This event is raised when the server send back a response */

alert(evt.target.responseText);

}

function uploadFailed(evt) {

alert("There was an error attempting to upload the file.");

}

function uploadCanceled(evt) {

alert("The upload has been canceled by the user or the browser dropped the connection.");

}

C#

///

/// 上传照片

///

///

///

public ActionResult ToLead(HttpPostedFileBase[] fileToUpload)

{

try

{

string FileUrl = string.Empty;

foreach (HttpPostedFileBase file in fileToUpload)

{

string path = System.IO.Path.Combine(Server.MapPath("~/Mers"), System.IO.Path.GetFileName(file.FileName));

file.SaveAs(path);

FileUrl = path;

FileStream Pic = new FileStream(path, FileMode.Open);

byte[] PicByte = new byte[Pic.Length];

Pic.Read(PicByte, 0, (int)Pic.Length);

Pic.Close();

}

return Content("上传成功");

}

catch

{

return Content("上传失败");

}

}