javascript jquery - How can I upload files asynchronously?

example ajax (25)

I would like to upload a file asynchronously with jQuery. This is my HTML:

<input type="file" id="file" name="file" size="10"/>
<input id="uploadbutton" type="button" value="Upload"/>

And here my Jquery code:

$(document).ready(function () {
    $("#uploadbutton").click(function () {
        var filename = $("#file").val();

            type: "POST",
            url: "",
            enctype: 'multipart/form-data',
            data: {
                file: filename
            success: function () {
                alert("Data Uploaded: ");

Instead of the file being uploaded, I am only getting the filename. What can I do to fix this problem?

Current Solution

I am using the jQuery Form Plugin to upload files.


Convert file to base64 using |HTML5's readAsDataURL() or some base64 encoder. Fiddle here

var reader = new FileReader();

        reader.onload = function(readerEvt) {
            var binaryString =;
            document.getElementById("base64textarea").value = btoa(binaryString);


Then to retrieve:"data:application/octet-stream;base64," + base64);

You can upload simply with jQuery .ajax().


<form id="upload-form">
        <label for="file">File:</label>
        <input type="file" id="file" name="file" />
        <progress class="progress" value="0" max="100"></progress>
    <hr />
    <input type="submit" value="Submit" />


.progress { display: none; }


$(document).ready(function(ev) {
    $("#upload-form").on('submit', (function(ev) {
            xhr: function() {
                var progress = $('.progress'),
                    xhr = $.ajaxSettings.xhr();


                xhr.upload.onprogress = function(ev) {
                    if (ev.lengthComputable) {
                        var percentComplete = parseInt((ev.loaded / * 100);
                        if (percentComplete === 100) {

                return xhr;
            url: 'upload.php',
            type: 'POST',
            data: new FormData(this),
            contentType: false,
            cache: false,
            processData: false,
            success: function(data, status, xhr) {
                // ...
            error: function(xhr, status, error) {
                // ...

A modern approach without Jquery is to use the FileList object you get back from <input type="file"> when user selects a file(s) and then use Fetch to post the FileList wrapped around a FormData object.

// The input DOM element
const inputElement = document.querySelector('input');

// Listen for a file submit from user
inputElement.addEventListener('change', () => {
    const data = new FormData()
    data.append('file', inputElement.files[0])
    data.append('imageName', 'flower')

    // Post to server
    fetch('/uploadImage', {
        method: 'POST',
        body: data

2017 Update: It still depends on the browsers your demographic uses.

An important thing to understand with the "new" HTML5 file API is that is wasn't supported until IE 10. If the specific market you're aiming at has a higher-than-average prepensity toward older versions of Windows, you might not have access to it.

Going into 2017, about 5% of browsers are one of IE 6, 7, 8 or 9. If you head into a big corporation (eg this is a B2B tool, or something you're delivering for training) that number can rocket. Just a few months ago —in 2016— I dealt with a company using IE8 on over 60% of their machines.

So before you do anything: check what browser your users use. If you don't, you'll learn a quick and painful lesson in why "works for me" isn't good enough in a deliverable to a client.

My answer from 2008 follows.

However, there are viable non-JS methods of file uploads. You can create an iframe on the page (that you hide with CSS) and then target your form to post to that iframe. The main page doesn't need to move.

It's a "real" post so it's not wholly interactive. If you need status you need something server-side to process that. This varies massively depending on your server. ASP.NET has nicer mechanisms. PHP plain fails, but you can use Perl or Apache modifications to get around it.

If you need multiple file-uploads, it's best to do each file one at a time (to overcome maximum file upload limits). Post the first form to the iframe, monitor its progress using the above and when it has finished, post the second form to the iframe, and so on.

Or use a Java/Flash solution. They're a lot more flexible in what they can do with their posts...

Simple Ajax Uploader is another option:

  • Cross-browser -- works in IE7+, Firefox, Chrome, Safari, Opera
  • Supports multiple, concurrent uploads -- even in non-HTML5 browsers
  • No flash or external CSS -- just one 5Kb Javascript file
  • Optional, built-in support for fully cross-browser progress bars (using PHP's APC extension)
  • Flexible and highly customizable -- use any element as upload button, style your own progress indicators
  • No forms required, just provide an element that will serve as upload button
  • MIT license -- free to use in commercial project

Example usage:

var uploader = new ss.SimpleUpload({
    button: $('#uploadBtn'), // upload button
    url: '/uploadhandler', // URL of server-side upload handler
    name: 'userfile', // parameter name of the uploaded file
    onSubmit: function() {
        this.setProgressBar( $('#progressBar') ); // designate elem as our progress bar
    onComplete: function(file, response) {
        // do whatever after upload is finished

You can use

$(function() {
        height        : 30,
        swf           : '/uploadify/uploadify.swf',
        uploader      : '/uploadify/uploadify.php',
        width         : 120


This AJAX file upload jQuery plugin uploads the file somehwere, and passes the response to a callback, nothing else.

  • It does not depend on specific HTML, just give it a <input type="file">
  • It does not require your server to respond in any particular way
  • It does not matter how many files you use, or where they are on the page

-- Use as little as --

  'action': '/upload.php'

-- or as much as --

  'action': '/upload.php',
  'params': {
    'extra': 'info'
  'onComplete': function(response) {
    console.log('custom handler for file:');
  'onStart': function() {
    if(weWantedTo) return false; // cancels upload
  'onCancel': function() {
    console.log('no file selected');

With HTML5 you can make file uploads with Ajax and jQuery. Not only that, you can do file validations (name, size, and MIME type) or handle the progress event with the HTML5 progress tag (or a div). Recently I had to make a file uploader, but I didn't want to use Flash nor Iframes or plugins and after some research I came up with the solution.


<form enctype="multipart/form-data">
    <input name="file" type="file" />
    <input type="button" value="Upload" />

First, you can do some validation if you want. For example, in the onChange event of the file:

$(':file').on('change', function() {
    var file = this.files[0];
    if (file.size > 1024) {
        alert('max upload size is 1k')

    // Also see .name, .type

Now the Ajax submit with the button's click:

$(':button').on('click', function() {
        // Your server script to process the upload
        url: 'upload.php',
        type: 'POST',

        // Form data
        data: new FormData($('form')[0]),

        // Tell jQuery not to process data or worry about content-type
        // You *must* include these options!
        cache: false,
        contentType: false,
        processData: false,

        // Custom XMLHttpRequest
        xhr: function() {
            var myXhr = $.ajaxSettings.xhr();
            if (myXhr.upload) {
                // For handling the progress of the upload
                myXhr.upload.addEventListener('progress', function(e) {
                    if (e.lengthComputable) {
                            value: e.loaded,
                } , false);
            return myXhr;

As you can see, with HTML5 (and some research) file uploading not only becomes possible but super easy. Try it with Google Chrome as some of the HTML5 components of the examples aren't available in every browser.

jQuery Uploadify is another good plugin which I have used before to upload files. The JavaScript code is as simple as the following: code. However, the new version does not work in Internet Explorer.

    'swf': '/public/js/uploadify.swf',
    'uploader': '/Upload.ashx?formGuid=' + $('#formGuid').val(),
    'cancelImg': '/public/images/uploadify-cancel.png',
    'multi': true,
    'onQueueComplete': function (queueData) {
        // ...
    'onUploadStart': function (file) {
        // ...

I have done a lot of searching and I have come to another solution for uploading files without any plugin and only with ajax. The solution is as below:

$(document).ready(function () {
    $('#btn_Upload').live('click', AjaxFileUpload);

function AjaxFileUpload() {
    var fileInput = document.getElementById("#Uploader");
    var file = fileInput.files[0];
    var fd = new FormData();
    fd.append("files", file);
    var xhr = new XMLHttpRequest();"POST", 'Uploader.ashx');
    xhr.onreadystatechange = function () {
        if (xhr.readyState == 4) {
        else if (uploadResult == 'success')

var formData=new FormData();

    type: 'POST',
    cache: false,
    contentType: false,
    processData: false,
    success:function(data){ }

You can use form data to post all your values including images.

A solution I found was to have the <form> target a hidden iFrame. The iFrame can then run JS to display to the user that it's complete (on page load).

You can do it in vanilla JavaScript pretty easily. Here's a snippet from my current project:

var xhr = new XMLHttpRequest();
xhr.upload.onprogress = function(e) {
    var percent = (e.position/ e.totalSize);
    // Render a pretty progress bar
xhr.onreadystatechange = function(e) {
    if(this.readyState === 4) {
        // Handle file upload complete
};'POST', '/upload', true);
xhr.setRequestHeader('X-FileName',; // Pass the filename along

It is an old question, but still has no answer correct answer, so:

Have you tried jQuery-File-Upload ?

Here is an example from the link above -> 1 that might solve your problem:

    add: function (e, data) {
        var that = this;
        $.getJSON('/example/url', function (result) {
            data.formData = result; // e.g. {id: 123}
      , e, data);

Sample: If you use jQuery, you can do easy to an upload file. This is a small and strong jQuery plugin,


var $bar   = $('.ProgressBar');
  dataType: 'json',

  beforeSend: function(xhr) {
    var percentVal = '0%';

  uploadProgress: function(event, position, total, percentComplete) {
    var percentVal = percentComplete + '%';

  success: function(response) {
    // Response

I hope it would be helpful

The simplest and most robust way I have done this in the past, is to simply target a hidden iFrame tag with your form - then it will submit within the iframe without reloading the page.

That is if you don't want to use a plugin, JavaScript or any other forms of "magic" other than HTML. Of course you can combine this with JavaScript or what have you...

<form target="iframe" action="" method="post" enctype="multipart/form-data">
    <input name="file" type="file" />
    <input type="button" value="Upload" />

<iframe name="iframe" id="iframe" style="display:none" ></iframe>

You can also read the contents of the iframe onLoad for server errors or success responses and then output that to user.

Chrome, iFrames, and onLoad

-note- you only need to keep reading if you are interested in how to setup a UI blocker when doing uploading/downloading

Currently Chrome doesn't trigger the onLoad event for the iframe when it's used to transfer files. Firefox, IE, and Edge all fire the onload event for file transfers.

The only solution that I found works for Chrome was to use a cookie.

To do that basically when the upload/download is started:

  • [Client Side] Start an interval to look for the existence of a cookie
  • [Server Side] Do whatever you need to with the file data
  • [Server Side] Set cookie for client side interval
  • [Client Side] Interval sees the cookie and uses it like the onLoad event. For example you can start a UI blocker and then onLoad ( or when cookie is made ) you remove the UI blocker.

Using a cookie for this is ugly but it works.

I made a jQuery plugin to handle this issue for Chrome when downloading, you can find here

The same basic principal applies to uploading, as well.

To use the downloader ( include the JS, obviously )

     "onComplete" : function(){
          $('#uiBlocker').css('display', 'none'); //hide ui blocker on complete

 $('somebuttion').click( function(){
      $('#uiBlocker').css('display', 'block'); //block the UI
      $('body').iDownloader('download', 'htttp://');

And on the server side, just before transferring the file data, create the cookie

 setcookie('iDownloader', true, time() + 30, "/");

The plugin will see the cookie, and then trigger the onComplete callback.

You can do the Asynchronous Multiple File uploads using JavaScript or jQuery and that to without using any plugin. You can also show the real time progress of file upload in the progress control. I have come across 2 nice links -

  1. ASP.NET Web Forms based Mulitple File Upload Feature with Progress Bar
  2. ASP.NET MVC based Multiple File Upload made in jQuery

The server side language is C# but you can do some modification for making it work with other language like PHP.

File Upload ASP.NET Core MVC:

In the View create file upload control in html:

<form method="post" asp-action="Add" enctype="multipart/form-data">
    <input type="file" multiple name="mediaUpload" />
    <button type="submit">Submit</button>

Now create action method in your controller:

public async Task<IActionResult> Add(IFormFile[] mediaUpload)
    //looping through all the files
    foreach (IFormFile file in mediaUpload)
        //saving the files
        string path = Path.Combine(hostingEnvironment.WebRootPath, "some-folder-path"); 
        using (var stream = new FileStream(path, FileMode.Create))
            await file.CopyToAsync(stream);

hostingEnvironment variable is of type IHostingEnvironment which can be injected to the controller using dependency injection, like:

private IHostingEnvironment hostingEnvironment;
public MediaController(IHostingEnvironment environment)
    hostingEnvironment = environment;

Using HTML5 and JavaScript, uploading async is quite easy, I create the uploading logic along with your html, this is not fully working as it needs the api, but demonstrate how it works, if you have the endpoint called /upload from root of your website, this code should work for you:

const asyncFileUpload = () => {
  const fileInput = document.getElementById("file");
  const file = fileInput.files[0];
  const uri = "/upload";
  const xhr = new XMLHttpRequest();
  xhr.upload.onprogress = e => {
    const percentage = e.loaded /;
  xhr.onreadystatechange = e => {
    if (xhr.readyState === 4 && xhr.status === 200) {
      console.log("file uploaded");
  };"POST", uri, true);
  <input type="file" id="file" name="file" size="10" />
  <input onclick="asyncFileUpload()" id="upload" type="button" value="Upload" />

Also some further information about XMLHttpReques:

The XMLHttpRequest Object

All modern browsers support the XMLHttpRequest object. The XMLHttpRequest object can be used to exchange data with a web server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page.

Create an XMLHttpRequest Object

All modern browsers (Chrome, Firefox, IE7+, Edge, Safari, Opera) have a built-in XMLHttpRequest object.

Syntax for creating an XMLHttpRequest object:

variable = new XMLHttpRequest();

Access Across Domains

For security reasons, modern browsers do not allow access across domains.

This means that both the web page and the XML file it tries to load, must be located on the same server.

The examples on W3Schools all open XML files located on the W3Schools domain.

If you want to use the example above on one of your own web pages, the XML files you load must be located on your own server.

For more details, you can continue reading here...

Wrapping up for future readers.

Asynchronous File Upload

With HTML5

You can upload files with jQuery using the $.ajax() method if FormData and the File API are supported (both HTML5 features).

You can also send files without FormData but either way the File API must be present to process files in such a way that they can be sent with XMLHttpRequest (Ajax).

  url: 'file/destination.html', 
  type: 'POST',
  data: new FormData($('#formWithFiles')[0]), // The form with the file inputs.
  processData: false,
  contentType: false                    // Using FormData, no need to process data.
  console.log("Success: Files sent!");
  console.log("An error occurred, the files couldn't be sent!");

For a quick, pure JavaScript (no jQuery) example see "Sending files using a FormData object".


When HTML5 isn't supported (no File API) the only other pure JavaScript solution (no Flash or any other browser plugin) is the hidden iframe technique, which allows to emulate an asynchronous request without using the XMLHttpRequest object.

It consists of setting an iframe as the target of the form with the file inputs. When the user submits a request is made and the files are uploaded but the response is displayed inside the iframe instead of re-rendering the main page. Hiding the iframe makes the whole process transparent to the user and emulates an asynchronous request.

If done properly it should work virtually on any browser, but it has some caveats as how to obtain the response from the iframe.

In this case you may prefer to use a wrapper plugin like Bifröst which uses the iframe technique but also provides a jQuery Ajax transport allowing to send files with just the $.ajax() method like this:

  url: 'file/destination.html', 
  type: 'POST',
  // Set the transport to use (iframe means to use Bifröst)
  // and the expected data type (json in this case).
  dataType: 'iframe json',                                
  fileInputs: $('input[type="file"]'),  // The file inputs containing the files to send.
  data: { msg: 'Some extra data you might need.'}
  console.log("Success: Files sent!");
  console.log("An error occurred, the files couldn't be sent!");


Bifröst is just a small wrapper that adds fallback support to jQuery's ajax method, but many of the aforementioned plugins like jQuery Form Plugin or jQuery File Upload include the whole stack from HTML5 to different fallbacks and some useful features to ease out the process. Depending on your needs and requirements you might want to consider a bare implementation or either of this plugins.

I've written this up in a Rails environment. It's only about five lines of JavaScript, if you use the lightweight jQuery-form plugin.

The challenge is in getting AJAX upload working as the standard remote_form_for doesn't understand multi-part form submission. It's not going to send the file data Rails seeks back with the AJAX request.

That's where the jQuery-form plugin comes into play.

Here’s the Rails code for it:

<% remote_form_for(:image_form, 
                   :url => { :controller => "blogs", :action => :create_asset }, 
                   :html => { :method => :post, 
                              :id => 'uploadForm', :multipart => true }) 
                                                                        do |f| %>
 Upload a file: <%= f.file_field :uploaded_data %>
<% end %>

Here’s the associated JavaScript:

$('#uploadForm input').change(function(){
  beforeSubmit: function(a,f,o) {
   o.dataType = 'json';
  complete: function(XMLHttpRequest, textStatus) {
   // XMLHttpRequest.responseText will contain the URL of the uploaded image.
   // Put it in an image element you create, or do with it what you will.
   // For example, if you have an image elemtn with id "my_image", then
   //  $('#my_image').attr('src', XMLHttpRequest.responseText);
   // Will set that image tag to display the uploaded image.

And here’s the Rails controller action, pretty vanilla:

 @image =[:image_form])
 render :text => @image.public_filename

I’ve been using this for the past few weeks with Bloggity, and it’s worked like a champ.

This is my solution.

<form enctype="multipart/form-data">    

    <div class="form-group">
        <label class="control-label col-md-2" for="apta_Description">Description</label>
        <div class="col-md-10">
            <input class="form-control text-box single-line" id="apta_Description" name="apta_Description" type="text" value="">

    <input name="file" type="file" />
    <input type="button" value="Upload" />

and the js


    $(':button').click(function () {
        var formData = new FormData($('form')[0]);
            url: '@Url.Action("Save", "Home")',  
            type: 'POST',                
            success: completeHandler,
            data: formData,
            cache: false,
            contentType: false,
            processData: false

    function completeHandler() {


public ActionResult Save(string apta_Description, HttpPostedFileBase file)
    return Json(":)");

Note: This answer is outdated, it is now possible to upload files using XHR.

You cannot upload files using XMLHttpRequest (Ajax). You can simulate the effect using an iframe or Flash. The excellent jQuery Form Plugin that posts your files through an iframe to get the effect.

I have been using the below script to upload images which happens to work fine.


<input id="file" type="file" name="file"/>
<div id="response"></div>


    var input = document.getElementById("file");
    var formdata = false;
    if (window.FormData) {
        formdata = new FormData();
    input.addEventListener("change", function (evt) {
        var i = 0, len = this.files.length, img, reader, file;

        for ( ; i < len; i++ ) {
            file = this.files[i];

            if (!!file.type.match(/image.*/)) {
                if ( window.FileReader ) {
                    reader = new FileReader();
                    reader.onloadend = function (e) {
                        //showUploadedItem(, file.fileName);

                if (formdata) {
                    formdata.append("image", file);

                if (formdata) {
                    jQuery('div#response').html('<br /><img src="ajax-loader.gif"/>');

                        url: "upload.php",
                        type: "POST",
                        data: formdata,
                        processData: false,
                        contentType: false,
                        success: function (res) {
                         jQuery('div#response').html("Successfully uploaded");
                alert('Not a vaild image!');

    }, false);


I use response div to show the uploading animation and response after upload is done.

Best part is you can send extra data such as ids & etc with the file when you use this script. I have mention it extra-data as in the script.

At the PHP level this will work as normal file upload. extra-data can be retrieved as $_POST data.

Here you are not using a plugin and stuff. You can change the code as you want. You are not blindly coding here. This is the core functionality of any jQuery file upload. Actually Javascript.

window.location.reload() will reload from the server and will load all your data, scripts, images, etc. again.

So if you just want to refresh the HTML, the window.location = document.URL will return much quicker and with less traffic. But it will not reload the page if there is a hash (#) in the URL.

javascript jquery ajax asynchronous upload