HTML5上传文件显示进度

       下面我们使用Html 5的新特性file api实现上传文件，并显示上传文件进度百分比。意图是这样的，当选择文件时，显示当前文件信息。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：

      

    @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：

        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：

    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");
        }
    }

希望对您Web开发有帮助。您可能感兴趣文章:

用Html5与Asp.net MVC上传多个文件

作者：Petter Liu
出处：http://www.cnblogs.com/wintersun/
本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
该文章也同时发布在我的独立博客中-Petter Liu Blog。