HTML5上传文件显示进度的实现代码

这里我们是结合Asp.net MVC做为服务端，您也可以是其它的服务端语言。让我们看面这个片断的HTML：

复制代码代码如下:
@using (Html.BeginForm(\”Upload\”, \”Home\”, FormMethod.Post, new { enctype = \”multipart/form-data\” , id=\”form1\”}))
{
<div class=\”row\”>
<label for=\”file\”>
Upload Image:</label>
<input type=\”file\” name=\”fileToUpload\” id=\”fileToUpload\” multiple=\”multiple\” onchange=\”fileSelected();\” />
</div>
<div id=\”fileName\”>
</div>
<div id=\”fileSize\”>
</div>
<div id=\”fileType\”>
</div>
<div class=\”row\”>
<input type=\”button\” onclick=\”uploadFile()\” value=\”Upload Image\” />
</div>
<div id=\”progressNumber\”>
</div>
}

相关的Javascript是这样的：

复制代码代码如下:
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/Upload\”);
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.\”);
}

上面是就原生的Javascript，在onchange事件执行fileSelected的function，在点击button执行了uploadFile的function，这里使用XMLHttpRequest实现ajax上传文件。 注意代码在Firefox 14 可以工作，IE 9目前不支持file api，可以参加这里。 服务端的代码很简单：

复制代码代码如下:
public class HomeController : Controller
{
public ActionResult Index()
{
return View();
}
/// <summary>
/// Uploads the specified files.
/// </summary>
/// <param name=\”fileToUpload\”>The files.</param>
/// <returns>ActionResult</returns>
[HttpPost]
public ActionResult Upload(HttpPostedFileBase[] fileToUpload)
{
foreach (HttpPostedFileBase file in fileToUpload)
{
string path = System.IO.Path.Combine(Server.MapPath(\”~/App_Data\”), System.IO.Path.GetFileName(file.FileName));
file.SaveAs(path);
}
ViewBag.Message = \”File(s) uploaded successfully\”;
return RedirectToAction(\”Index\”);
}
}

作者：Petter Liu
本知识来源于互联网索引，如有侵权请联系我们！