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Editorial Team
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Asked: 2026-05-31T06:41:11+00:00

I’m having problems trying to upload files using the latest XHR 2 along with

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I’m having problems trying to upload files using the latest XHR 2 along with PHP.

My code is as follows:

HTML…

<!doctype html>
<html>
    <head>
        <title>XHR Multiple File Upload</title>
        <link rel="stylesheet" type="text/css" href="upload.css">
    </head>
    <body>
        <input type="file" id="upload" multiple="true" accept="image/*">
        <a href="#" id="upload-link">Click here to upload multiple files</a>
        <script src="upload.js"></script>
    </body>
</html>

JavaScript

var formdata, link, input, doc = document;

if (window.FormData) {
    formdata = new FormData();
}

function init(){
    link = doc.getElementById("upload-link"),
    input = doc.getElementById("upload");

    link.addEventListener("click", process, false);
    input.addEventListener("change", displaySelectedFiles, false);
}

function process (e) {
    // If the input element is found then trigger the click event (which opens the file select dialog window)
    if (input) {
        input.click();
    }

    e.preventDefault();
}

function displaySelectedFiles(){
    // Once a user selects some files the 'change' event is triggered (along with this listener function)
    // We can access selected files via 'this.files' property object.
    var files = this.files,
        count = 0,
        len = files.length;

    while (count < len) {
        createImage(files[count]);
        count++;
    }

    var confirm = doc.createElement("input");
        confirm.type = "submit";
        confirm.value = "Upload these files";
        confirm.id = "confirm";

    doc.body.appendChild(confirm);

    confirm.addEventListener("click", uploadFiles, false);
}

function createImage (file) {
    var element = doc.createElement("img");
        element.file = file;
        element.classList.add("thumbnail");

    // We store the file object as a property of the image (for use later)
    doc.body.appendChild(element);

    // The FileReader object lets web applications asynchronously read the contents of files
    var reader = new FileReader();  

    reader.onload = (function (img) { 
        return function (e) { 
            img.src = e.target.result;
        }; 
    })(element);

    reader.readAsDataURL(file);
}

function uploadFiles(){
    var reader = new FileReader(),
        imgs = doc.querySelectorAll(".thumbnail"),
        count = 0,
        len = imgs.length;

    while (count < len) {
        // Once image file is read then we can 'send' the upload request
        reader.onload = function (e) {
            formdata.append("images[]", e.target.result);
        }
        reader.readAsDataURL(imgs[count].file);
        count++;
    }

    fileUpload();
}

function fileUpload(){
    var xhr = new XMLHttpRequest();

    function progressListener (e) {
        console.log("progressListener: ", e);
        if (e.lengthComputable) {
            var percentage = Math.round((e.loaded * 100) / e.total);
            console.log("Percentage loaded: ", percentage);
        }
    };

    function finishUpload (e) {
        console.log("Finished Percentage loaded: 100");
    };

    // XHR2 has an upload property with a 'progress' event
    xhr.upload.addEventListener("progress", progressListener, false);

    // XHR2 has an upload property with a 'load' event
    xhr.upload.addEventListener("load", finishUpload, false);

    // Begin uploading of file
    xhr.open("POST", "upload.php");

    xhr.onreadystatechange = function(){
        console.info("readyState: ", this.readyState);
        if (this.readyState == 4) {
            if ((this.status >= 200 && this.status <= 200) || this.status == 304) {
                if (this.responseText != "") {
                    console.warn(xhr.responseText);
                }
            }
        }
    };

    xhr.send(formdata);
}

window.addEventListener("DOMContentLoaded", init, false);

PHP (I wasn’t sure about the PHP code and found the below via this article http://net.tutsplus.com/tutorials/javascript-ajax/uploading-files-with-ajax/)

foreach ($_FILES["images"]["error"] as $key => $error) {  
    if ($error == UPLOAD_ERR_OK) {  
        $name = $_FILES["images"]["name"][$key];
        move_uploaded_file( $_FILES["images"]["tmp_name"][$key], "uploaded-images/" . $_FILES['images']['name'][$key]);
    }
}
echo "Successfully Uploaded Images";

I get the success message back, but no files uploaded into the relevant folder. I think either the formdata isn’t being stored properly via JavaScript OR it isn’t being passed to the server properly for PHP to access (or it could be that the PHP code I grabbed from that article linked to above just doesn’t work – as I’m not a PHP person I’m not 100% sure).

Any help would be greatly appreciated.

Kind regards,
Mark

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1 Answer

  1. Editorial Team

    The main issue was with how I was appending the image file object to the FormData object.

    A working version of the code can be found below and also on GitHub here: https://github.com/Integralist/XHR2-Multiple-File-Upload–with-PHP-

    HTML

    <!doctype html>
<html>
    <head>
        <title>XHR Multiple File Upload</title>
        <link rel="stylesheet" type="text/css" href="upload.css">
    </head>
    <body>
        <!-- the file input is hidden by CSS-->
        <input type="file" name="images" id="upload" multiple="true" accept="image/*">
        <a href="#" id="upload-link">Click here to upload multiple files</a>
        <div id="browsers">
            <p>As of March 2012 the following browsers support the required features to run this demo:</p>
            <ul>
                <li><a href="#">Firefox 4+ (current version 10)</a></li>
                <li><a href="#">Google Chrome 7+ (current version 17)</a></li>
            </ul>
        </div>
        <script src="upload.js"></script>
    </body>
</html>

    PHP

    $response = "";

foreach ($_FILES["images"]["error"] as $key => $error) { 
    if ($error == UPLOAD_ERR_OK) {  
        $name = $_FILES["images"]["name"][$key];
        move_uploaded_file( $_FILES["images"]["tmp_name"][$key], "uploaded-images/" . $_FILES['images']['name'][$key]);
        $response = "Files have been uploaded";
    } else {
        $response = $error;
    }
}

echo $response;

/*
Example of formdata passed through…

array(5) { 
    ["name"]=> array(4) { 
        [0]=> string(13) "Generic-2.jpg" 
        [1]=> string(13) "Generic-3.jpg" 
        [2]=> string(13) "Generic-4.jpg" 
        [3]=> string(13) "Generic-5.jpg" 
    } 
    ["type"]=> array(4) { 
        [0]=> string(10) "image/jpeg" 
        [1]=> string(10) "image/jpeg" 
        [2]=> string(10) "image/jpeg" 
        [3]=> string(10) "image/jpeg" 
    } 
    ["tmp_name"]=> array(4) { 
        [0]=> string(36) "/Applications/MAMP/tmp/php/phprzscxs" 
        [1]=> string(36) "/Applications/MAMP/tmp/php/php1cnfqk" 
        [2]=> string(36) "/Applications/MAMP/tmp/php/phpVkS89p" 
        [3]=> string(36) "/Applications/MAMP/tmp/php/phptSfmwt" 
    } 
    ["error"]=> array(4) { 
        [0]=> int(0) 
        [1]=> int(0) 
        [2]=> int(0) 
        [3]=> int(0) 
    } 
    ["size"]=> array(4) { 
        [0]=> int(130120) 
        [1]=> int(397627) 
        [2]=> int(578842) 
        [3]=> int(840531) 
    } 
} 
*/

    JavaScript

    /*
 * Required features:
 *      addEventListener (Google Chrome 1+, FF 1+, IE 9+, Opera 7+, Safari 1+)
 *      FileReader (Google Chrome 7+, FF 3.6+, IE 10+)
 *      FormData (Google Chrome 7+, FF 4+, Safari 5+)
 */
if (("addEventListener" in window) && ("FileReader" in window) && ("FormData" in window)) {
    window.addEventListener("DOMContentLoaded", init, false);
} else {
    alert("This demo wont work for you, sorry - please upgrade your web browser");
    document.getElementById("browsers").style.display = "block";
}

var formdata, link, input, doc = document;

function init(){
    formdata = new FormData()

    link = doc.getElementById("upload-link"),
    input = doc.getElementById("upload");

    // Now we know the browser supports the required features we can display the 'browse' button
    link.style.display = "inline";

    link.addEventListener("click", process, false);
    input.addEventListener("change", displaySelectedFiles, false);
}

function process (e) {
    // If the input element is found then trigger the click event (which opens the file select dialog window)
    if (input) {
        input.click();
    }

    e.preventDefault();
}

function displaySelectedFiles(){
    // Once a user selects some files the 'change' event is triggered (and this listener function is executed)
    // We can access selected files via 'this.files' property object.

    var img, reader, file;

    for (var i = 0, len = this.files.length; i < len; i++) {
        file = this.files[i];

        if (!!file.type.match(/image.*/)) {
            if (window.FileReader) {
                reader = new FileReader();
                reader.onloadend = function (e) { 
                    createImage(e.target.result, e);
                };
                reader.readAsDataURL(file);
            }

            if (formdata) {
                /*
                    The append method simply takes a key and a value. 
                    In our case, our key is images[]; 
                    By adding the square-brackets to the end, we make sure each time we append another value, 
                    we’re actually appending it to that array, instead of overwriting the image property.
                 */
                formdata.append("images[]", file);
            }
        }   
    }

    // We only need to create the 'upload' button once  
    if (!doc.getElementById("confirm")) {
        var confirm = doc.createElement("input");
            confirm.type = "submit";
            confirm.value = "Upload these files";
            confirm.id = "confirm";

        doc.body.appendChild(confirm);

        confirm.addEventListener("click", uploadFiles, false);
    }

    // We only need to create the 'clear' button once   
    if (!doc.getElementById("clear")) {
        var clear = doc.createElement("input");
            clear.type = "button";
            clear.value = "Clear these files";
            clear.id = "clear";

        doc.body.appendChild(clear);

        clear.addEventListener("click", function(){
            window.location.reload();
        }, false);
    }
}

function createImage (source, fileobj) {
    var element = doc.createElement("img");
        element.file = fileobj;
        element.className = "thumbnail";
        element.src = source;

    // We store the file object as a property of the image (for use later)
    doc.body.appendChild(element);
}

function uploadFiles(){
    var xhr = new XMLHttpRequest();

    function progressListener (e) {
        console.log("progressListener: ", e);
        if (e.lengthComputable) {
            var percentage = Math.round((e.loaded * 100) / e.total);
            console.log("Percentage loaded: ", percentage);
        }
    };

    function finishUpload (e) {
        console.log("Finished Percentage loaded: 100");
    };

    // XHR2 has an upload property with a 'progress' event
    xhr.upload.addEventListener("progress", progressListener, false);

    // XHR2 has an upload property with a 'load' event
    xhr.upload.addEventListener("load", finishUpload, false);

    // Begin uploading of file
    xhr.open("POST", "upload.php");

    xhr.onreadystatechange = function(){
        console.info("readyState: ", this.readyState);
        if (this.readyState == 4) {
            if ((this.status >= 200 && this.status < 300) || this.status == 304) {
                if (this.responseText != "") {
                    alert(xhr.responseText);
                }
            }
        }
    };

    xhr.send(formdata);
}
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