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原生的Javascript+Html 5的新特性file api+显示上传文件进度百分比+xhr实现文件上传

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Created: 2017年11月15日星期三 下午9:07:23 Latest updated:2020年2月5日星期三 下午11:06:03 views(1912)
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");
        }
    }



 

 

http://www.cnblogs.com/wintersun/archive/2012/08/30/2663408.html .