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<title>Html-Qrcode Demo</title>
<div id="qr-reader" style="width:500px"></div>
<div id="qr-reader-results"></div>
<script src=""></script>
<script src="html5-qrcode-demo.js"></script>
function docReady(fn) {
// see if DOM is already available
if (document.readyState === "complete" || document.readyState === "interactive") {
// call on next available tick
setTimeout(fn, 1);
} else {
document.addEventListener("DOMContentLoaded", fn);
docReady(function() {
var resultContainer = document.getElementById('qr-reader-results');
var lastResult, countResults = 0;
var html5QrcodeScanner = new Html5QrcodeScanner(
"qr-reader", { fps: 10, qrbox: 250 });
function onScanSuccess(decodedText, decodedResult) {
if (decodedText !== lastResult) {
lastResult = decodedText;
console.log(`Scan result = ${decodedText}`, decodedResult);
resultContainer.innerHTML += `<div>[${countResults}] - ${decodedText}</div>`;
// Optional: To close the QR code scannign after the result is found
// Optional callback for error, can be ignored.
function onScanError(qrCodeError) {
// This callback would be called in case of qr code scan error or setup error.
// You can avoid this callback completely, as it can be very verbose in nature.
html5QrcodeScanner.render(onScanSuccess, onScanError);
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virtualvoid commented Dec 14, 2020

not working on iOS, permissions denied.

edit: the website needs to be on HTTPS

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hasalfernando commented Dec 23, 2020


Does anyone know whether there is any possible solution to change the default width of video from 300px? Though I have set the width of div to 100%, video and canvas width of 300px is being overridden and video is getting cornered to the left. I want to know whether there is any possible way to adjust this width?

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virtuosodelared commented Jan 14, 2021

@matiazar If I recall correctly this can be achieved when you use the Html5Qrcode directly. In the demo I have consciously added logic for request permission every time - to both show demo and I think user should have control.

But at the API level, the permission is needed only once* (...)

Thanks for this great applicaction. I am using this qr reader in a pc with a webcam to read qrcodes, open urls from qr´s, and back again to the qr reader. So I would like to know if is possible to avoid give permissions again and also click in "start scanning" button. In this way, qr reader will be scanning automatically.
Please let me know if this is possible and how i can achieve it. Thanks in advance

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jmsousa commented Jan 27, 2021

Hi, I am trying to use in Blazor with the following code:

Blazor Page:
<div style="width: auto" id="reader"></div>' @code {
protected override async Task OnAfterRenderAsync(bool firstRender)
if (firstRender) await _jsRuntime.InvokeVoidAsync("Html5QrCode", DotNetObjectReference.Create(this));
await base.OnAfterRenderAsync(firstRender);

`function Html5QrCode () {
var html5QrCode = new Html5Qrcode("reader");
Html5Qrcode.getCameras().then(devices => {

    if (devices && devices.length) {

        var cameraId = devices[1].id;
        alert("cameraId: " + cameraId);

                fps: 10,    // Optional frame per seconds for qr code scanning
                qrbox: 250  // Optional if you want bounded box UI
            qrCodeMessage => {
                // do something when code is read
            errorMessage => {
                // parse error, ignore it.
                // alert(errorMessage);
            .catch(err => {
                // Start failed, handle it.
}).catch(err => {
    // handle err


I can read the camera id, but then I have the following error:
Cannot set property 'innerHTML' of null

João Sousa

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friendztech7 commented Feb 26, 2021

when i run code on phone it's show
error :- unable to query supported devices

Please Help Sir

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Take51 commented Mar 3, 2021

You code works super good. Anyway I need some help.
When I scanned the QR code, scanner was shutted down and give me a result from the scan.
Can I after this add some button like "Start a new scan" or "Scan another code"? Because now, when I want a new scan, I must reload the whole page..

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snatcoinOfficial commented Mar 18, 2021

Nice QR code reader.. but...
Does anyone know what permissions you need to add to Android Studio to get this to work within an Android app (as a webview)? I've added the camera and write external permissions.. but within the app it says "NotAllowedError: Permission denied". Though if I load up the url within Chrome it works fine. (The url is https)


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Reza-kavian commented Apr 13, 2021

In your site demo, in addition to qrcode, I can also scan barcodes. But when I transfer the source code to my project, it only reads qrcode but does not read barcodes

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viney-equinix commented Apr 25, 2021

Hi Everyone,

I am facing the issue with Html5Qrcode availability in global scope in my react typescript app. i am following this article ( to implement as Hook in my react-typescript app, could you please help me to fix this issue. how can i declare in .d.ts file.

What exactly you want to say in below comment
// eslint-disable-next-line
const html5qrCodeScanner = new Html5Qrcode(qrcodeMountNodeID);

How can i fix this issue, i am not getting Html5Qrcode in global scope event after following the complete steps ?

Please help

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haspden commented May 14, 2021

Hi Guys I have a lovely working example setup including some customisations of redirecting the user to a page with variables gathered from the QR code for processing, but I'm still stuck on how to enforce the rear camera...

Posted my general question here but could do with some input

I think the issue is I am using the simple version and applying my custom js inside resultContainer.innerHTML += and I need to be using the (start) method / PRO method instead, however I cant find any examples of this method?

@mebjas do you have any thoughts


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davidcbittner commented May 19, 2021

This routine is working for my needs and I have my code in there to process the qrCodeMessage and the .clear() does clear it however wipes the widget completely from the body. What's the procedure to stop scanning once you have success and stop the video feed etc as if you hit the stop button on the demo? I want to scan the code, stop video feed etc, process the message then be able to scan a new code. I can't seem to figure out how to start it again after the .clear() without refreshing the page.

function onScanSuccess(qrCodeMessage) {
// handle on success condition with the decoded message
// ^ this will stop the scanner (video feed) and clear the scan area.

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Jalil-Irfan commented Jun 7, 2021

In your site demo, in addition to qrcode, I can also scan barcodes. But when I transfer the source code to my project, it only reads qrcode but does not read barcodes

Yes i too couldnt scan anything except QR

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mebjas commented Jun 14, 2021

@Reza-kavian @Jalil-Irfan - Try latest version of the library (v2.0.9), it should read different formats listed in the readme.

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sergey-kukosh commented Aug 5, 2021

Hi mebjas
I found the one problem, I ecoded "1" to QR code, and this what I can't scan, it can't decode. Can you tell me where in the library I can see if I can fix it, thank you!
Screenshot 2021-08-05 at 11 08 57

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vyking60 commented Jan 3, 2022

Hi mebjas,
I am more or less new to web development. I tried your example but I get error:

scan:57 Uncaught ReferenceError: Html5QrcodeScanner is not defined

I have put in Handlebars layout:

<script src="" type="text/javascript">

and in handlebars view this:

QR Code Scanner

<script> var resultContainer = document.getElementById('qr-reader-results'); var lastResult, countResults = 0; function onScanSuccess(decodedText, decodedResult) { if (decodedText !== lastResult) { ++countResults; lastResult = decodedText; // Handle on success condition with the decoded message. console.log(`Scan result ${decodedText}`, decodedResult); } } var html5QrcodeScanner = new Html5QrcodeScanner( "qr-reader", { fps: 10, qrbox: 250 }); html5QrcodeScanner.render(onScanSuccess); </script>

I know it must be some 'basic' problem... Can you help?

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fopsycute commented Jan 5, 2022

hi mebjas, I tried using all ur format, but anytime I display it on browser(localhost) everything is always camera showing

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bkmattias commented Jan 25, 2022

Good evening. Is there a way to set it on image reader by default instead of scan first?

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apkc commented Aug 30, 2022

I seem to have an issue when the qrcode scanner is kept in between the

. When the scanner starts it prompts the permission with REQUEST CAMERA PERMISSIONS button. but since the button is not having any type"button" attribute by default, it is posting the form automatically which is unintended. how can the type="button" be added to prevent it? Thanks

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Macof08 commented Oct 10, 2022

@mwambajoshua for now, you can do this

function validURL(str) {
  var pattern = new RegExp('^(https?:\\/\\/)?'+ // protocol
    '((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|'+ // domain name
    '((\\d{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address
    '(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*'+ // port and path
    '(\\?[;&a-z\\d%_.~+=-]*)?'+ // query string
    '(\\#[-a-z\\d_]*)?$','i'); // fragment locator
  return !!pattern.test(str);

function onScanSuccess(qrCodeMessage) {
  if (validURL(qrCodeMessage)) {
    window.location.href = qrCodeMessage;

var html5QrcodeScanner = new Html5QrcodeScanner(
	"qr-reader", { fps: 10, qrbox: 250 });

@mebjas how can i add this script only the back camara? html5QrcodeScanner.render({ facingMode: { exact:"environment" } }, onScanSuccess); i cant :(

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