Html5-QRCode

(supports barcodes now 😃)

A cross-platform HTML5 QR code & barcode reader.

Use this lightweight library to easily / quickly integrate QR code, bar code, and other common code scanning capabilities to your web application.

• Supports easy scanning using an integrated webcam or camera in smartphones (Android / IOS).

• Supports scanning codes from files or default cameras on smartphones.

• Recently Added Supports bar code scanning in various formats.

• Supports two kinds of APIs

  • Html5QrcodeScanner — End-to-end scanner with UI, integrate with less than ten lines of code.
  • Html5Qrcode — Powerful set of APIs you can use to build your UI without worrying about camera setup, handling permissions, reading codes, etc.

> Support for scanning local files on the device is a new addition and helpful for the web browser which does not support inline web-camera access in smartphones. Note: This doesn't upload files to any server — everything is done locally.

Demo at scanapp.org	Demo at qrcode.minhazav.dev - Scanning different types of codes

Notice

UX/UXD/UXR help wanted: We are looking to improve user experience of this code scanning library — if you are interested in making this experience better for both developers and end users, please share your ideas, thoughts, inputs in this discussion

Supported platforms

We are working continuously on adding support for more and more platforms. If you find a platform or a browser where the library is not working, please feel free to file an issue. Check the demo link to test it out.

Legends

• Means full support — inline webcam and file based
• Means partial support — only file based, webcam in progress

PC / Mac

Firefox	Chrome	Safari	Opera	Edge

Android

Chrome	Firefox	Edge	Opera	Opera Mini	UC

IOS

Safari	Chrome	Firefox	Edge
	*	*

> * Supported for IOS versions >= 15.1 > > Before version 15.1, Webkit for IOS is used by Chrome, Firefox, and other browsers in IOS and they do not have webcam permissions yet. There is an ongoing issue on fixing the support for iOS - issue/14

Framework support

The library can be easily used with several other frameworks, I have been adding examples for a few of them and would continue to add more.

Html5	VueJs	ElectronJs	React

Supported Code formats

Code scanning is dependent on Zxing-js library. We will be working on top of it to add support for more types of code scanning. If you feel a certain type of code would be helpful to have, please file a feature request.

Code	Example
QR Code
AZTEC
CODE_39
CODE_93
CODE_128
ITF
EAN_13
EAN_8
PDF_417
UPC_A
UPC_E
DATA_MATRIX
MAXICODE*
RSS_14*
RSS_EXPANDED*

> *Formats are not supported by our experimental integration with native > BarcodeDetector API integration (Read more).

Description - View Demo

> See an end to end scanner experience at scanapp.org.

This is a cross-platform JavaScript library to integrate QR code, bar codes & a few other types of code scanning capabilities to your applications running on HTML5 compatible browser.

Supports:

• Querying camera on the device (with user permissions)
• Rendering live camera feed, with easy to use user interface for scanning
• Supports scanning a different kind of QR codes, bar codes and other formats
• Supports selecting image files from the device for scanning codes

How to use

> For full information read this article.

Download the script from release page or install using npm with:

npm i html5-qrcode

Add an element you want to use as a placeholder for QR Code scanner

<div width="600px" id="reader"></div>

> Ideally do not set the height of this container as the height should depend on the height of the video feed from the camera. The library would honor the existing width, otherwise apply the default width. The height is derived from the aspect ratio of the video feed.

Using directly in browser without any loader

If you are not using any loader, you can get the latest UMD javascript code in production from https://unpkg.com/html5-qrcode.

> It's not mandatory to set the height and width of the HTML element. If provided, the library would try to honor it. If it's not set, the library would set a default width and derive the height based on the input image's aspect ratio.

Add an Input element for supporting file selection like this:

<input accept="image/*" id="qr-input-file" type="file">


<input capture="" accept="image/*" id="qr-input-file" type="file">

Find more information about this at developers.google.com.

And in JavaScript code initialize the object and attach listener like this:

const html5QrCode = new Html5Qrcode(/* element id */ "reader");
// File based scanning
const fileinput = document.getElementById('qr-input-file');
fileinput.addEventListener('change', e => {
  if (e.target.files.length == 0) {
    // No file selected, ignore 
    return;
  }

  const imageFile = e.target.files[0];
  // Scan QR Code
  html5QrCode.scanFile(imageFile, true)
  .then(decodedText => {
    // success, use decodedText
    console.log(decodedText);
  })
  .catch(err => {
    // failure, handle it.
    console.log(`Error scanning file. Reason: ${err}`)
  });
});

// Note: Current public API `scanFile` only returns the decoded text. There is
// another work in progress API (in beta) which returns a full decoded result of
// type `QrcodeResult` (check interface in src/core.ts) which contains the
// decoded text, code format, code bounds, etc.
// Eventually, this beta API will be migrated to the public API.

> Note that inline scanning and file-based scanning are mutually exclusive at the moment. This means you can only use one of them at a time. I'll soon be adding support for the option to have both if the requirement comes in. If you want to use both, use html5QrCode#clear() method to clear the canvas.

Demo

Scan this image or visit blog.minhazav.dev/research/html5-qrcode.html

For more information

Check these articles on how to use this library:

• QR and barcode scanner using HTML and JavaScript
• HTML5 QR Code scanning — launched v1.0.1 without jQuery dependency and refactored Promise based APIs.
• HTML5 QR Code scanning with JavaScript — Support for scanning the local file and using default camera added (v1.0.5)

Screenshots

Figure: Screenshot from Google Chrome running on MacBook Pro

Documentation

Following methods are available in this library (typescript definition)

/** Camera Device interface. */
interface CameraDevice {
  id: string;
  label: string;
}

/** Different states of scanner */
enum Html5QrcodeScannerState {
  // Indicates the sanning is not running or user is using file based
  // scanning.
  NOT_STARTED = 0,
  // Camera scan is running.
  SCANNING,
  // Camera scan is paused but camera is running.
  PAUSED,
}

/**
 * Code formats supported by this library.
 */
enum Html5QrcodeSupportedFormats {
  QR_CODE = 0,
  AZTEC,
  CODABAR,
  CODE_39,
  CODE_93,
  CODE_128,
  DATA_MATRIX,
  MAXICODE,
  ITF,
  EAN_13,
  EAN_8,
  PDF_417,
  RSS_14,
  RSS_EXPANDED,
  UPC_A,
  UPC_E,
  UPC_EAN_EXTENSION,
}

/** Defines dimension for QR Code Scanner. */
interface QrDimensions {
  width: number;
  height: number;
}

/**
 * A function that takes in the width and height of the video stream 
 * and returns QrDimensions.
 * 
 * Viewfinder refers to the video showing camera stream.
 */
type QrDimensionFunction =
    (viewfinderWidth: number, viewfinderHeight: number) => QrDimensions;

/** Format of detected code. */
class QrcodeResultFormat {
  public readonly format: Html5QrcodeSupportedFormats;
  public readonly formatName: string;
}

/** Detailed scan result. */
interface QrcodeResult {
  /** Decoded text. */
  text: string;

  /** Format that was successfully scanned. */
  format?: QrcodeResultFormat,
}

/** QrCode result object. */
interface Html5QrcodeResult {
  decodedText: string;
  result: QrcodeResult;
}

/** Type for a callback for a successful code scan. */
type QrcodeSuccessCallback
  = (decodedText: string, result: Html5QrcodeResult) => void;

/** Type for a callback for failure during code scan. */
type QrcodeErrorCallback
  = (errorMessage: string, error: Html5QrcodeError) => void;

/**
 * Interface for configuring {@class Html5Qrcode} class instance.
 */
interface Html5QrcodeConfigs {
  /**
   * Array of formats to support of type {@type Html5QrcodeSupportedFormats}.
   */
  formatsToSupport: Array | undefined;
}

/** Configuration for creating {@class Html5Qrcode}. */
interface Html5QrcodeFullConfig extends Html5QrcodeConfigs {
  /**
   * If true, all logs would be printed to console. False by default.
   */
  verbose: boolean | undefined;
}

interface Html5QrcodeCameraScanConfig {
  /**
   * Optional, Expected framerate of QR code scanning. example { fps: 2 } means the
   * scanning would be done every 500 ms.
   */
  fps: number | undefined;

  /**
   * Optional, edge size, dimension or calculator function for QR scanning
   * box, the value or computed value should be smaller than the width and
   * height of the full region.
   * 
   * This would make the scanner look like this:
   *          ----------------------
   *          |********************|
   *          |******,,,,,,,,,*****|      <--- shaded region
   *          |******|       |*****|      <--- non shaded region would be
   *          |******|       |*****|          used for QR code scanning.
   *          |******|_______|*****|
   *          |********************|
   *          |********************|
   *          ----------------------
   * 
   * Instance of {@interface QrDimensions} can be passed to construct a non
   * square rendering of scanner box. You can also pass in a function of type
   * {@type QrDimensionFunction} that takes in the width and height of the
   * video stream and return QR box size of type {@interface QrDimensions}.
   * 
   * If this value is not set, no shaded QR box will be rendered and the scanner
   * will scan the entire area of video stream.
   */
  qrbox?: number | QrDimensions | QrDimensionFunction | undefined;

  /**
   * Optional, Desired aspect ratio for the video feed. Ideal aspect ratios
   * are 4:3 or 16:9. Passing very wrong aspect ratio could lead to video feed
   * not showing up.
   */
  aspectRatio?: number | undefined;

  /**
   * Optional, if {@code true} flipped QR Code won't be scanned. Only use this
   * if you are sure the camera cannot give mirrored feed if you are facing
   * performance constraints.
   */
  disableFlip?: boolean | undefined;

  /*
   * Optional, @beta(this config is not well supported yet).
   *
   * Important: When passed this will override other parameters like
   * 'cameraIdOrConfig' or configurations like 'aspectRatio'.
   * 'videoConstraints' should be of type {@code MediaTrackConstraints} as
   * defined in
   * https://developer.mozilla.org/en-US/docs/Web/API/MediaTrackConstraints
   * and is used to specify a variety of video or camera controls like:
   * aspectRatio, facingMode, frameRate, etc.
   */
  videoConstraints?: MediaTrackConstraints | undefined;
}

/**
 * Interface for controlling different aspects of {@class Html5QrcodeScanner}.
 */
interface Html5QrcodeScannerConfig
  extends Html5QrcodeCameraScanConfig, Html5QrcodeConfigs {

  /**
   * If {@code true} the library will remember if the camera permissions
   * were previously granted and what camera was last used. If the permissions
   * is already granted for "camera", QR code scanning will automatically
   * start for previously used camera.
   */
  rememberLastUsedCamera?: boolean | undefined;

  /**
   * Sets the desired scan types to be supported in the scanner.
   * 
   *  - Not setting a value will follow the default order supported by
   *      library.
   *  - First value would be used as the default value. Example:
   *    - [SCAN_TYPE_CAMERA, SCAN_TYPE_FILE]: Camera will be default type,
   *      user can switch to file based scan.
   *    - [SCAN_TYPE_FILE, SCAN_TYPE_CAMERA]: File based scan will be default
   *      type, user can switch to camera based scan.
   *  - Setting only value will disable option to switch to other. Example:
   *    - [SCAN_TYPE_CAMERA] - Only camera based scan supported.
   *    - [SCAN_TYPE_FILE] - Only file based scan supported.
   *  - Setting wrong values or multiple values will fail.
   */
  supportedScanTypes: Array | [];
};

class Html5Qrcode {
  /**
   * Returns a Promise with a list of all cameras supported by the device.
   */
  static getCameras(): Array // Returns a Promise

  /**
   * Initialize QR Code scanner.
   * 
   * @param elementId - Id of the HTML element.
   * @param verbose - optional configuration object
   */
  constructor(elementId: string, config:  Html5QrcodeFullConfig | undefined) {}

  /**
   * Start scanning QR codes or barcodes for a given camera.
   * 
   * @param cameraIdOrConfig Identifier of the camera, it can either be the
   *  camera id retrieved from {@code Html5Qrcode#getCameras()} method or
   *  object with facing mode constraint.
   * @param configuration Extra configurations to tune the code scanner.
   * @param qrCodeSuccessCallback Callback called when an instance of a QR
   * code or any other supported bar code is found.
   * @param qrCodeErrorCallback Callback called in cases where no instance of
   * QR code or any other supported bar code is found.
   */
  start(
    cameraIdOrConfig: Html5QrcodeIdentifier,
    configuration: Html5QrcodeCameraScanConfig | undefined,
    qrCodeSuccessCallback: QrcodeSuccessCallback | undefined,
    qrCodeErrorCallback: QrcodeErrorCallback | undefined,
  ): Promise {}

  /**
   * Pauses the ongoing scan.
   * 
   * @param shouldPauseVideo (Optional, default = false) If {@code true} the
   * video will be paused.
   * 
   * @throws error if method is called when scanner is not in scanning state.
   */
  pause(shouldPauseVideo?: boolean);

  /**
   * Resumes the paused scan.
   * 
   * If the video was previously paused by setting {@code shouldPauseVideo}
   * to {@code true} in {@link Html5Qrcode#pause(shouldPauseVideo)}, calling
   * this method will resume the video.
   *
   * Note: with this caller will start getting results in success and error
   * callbacks.
   * 
   * @throws error if method is called when scanner is not in paused state.
   */
  resume();

  /**
   * Stops streaming QR Code video and scanning. 
   */
  stop(): Promise {}

  /**
   * Gets state of the camera scan.
   *
   * @returns state of type {@enum ScannerState}.
   */
  getState(): Html5QrcodeScannerState;

  /**
   * Scans an Image File for QR Code.
   *
   * This feature is mutually exclusive to camera-based scanning, you should
   * call stop() if the camera-based scanning was ongoing.
   *
   * @param imageFile a local file with Image content.
   * @param showImage if true, the Image will be rendered on given element.
   *
   * @returns Promise with decoded QR code string on success.
   */
  scanFile(
    imageFile: File,
    /* default=true */ showImage: boolean | undefined): Promise {}

  /**
   * Clears the existing canvas.
   * 
   * Note: in case of ongoing web-cam based scan, it needs to be explicitly
   * closed before calling this method, else it will throw an exception.
   */
  clear(): void {}  // Returns void
}

class Html5QrcodeScanner {
  /**
   * Creates an instance of this class.
   *
   * @param elementId Id of the HTML element.
   * @param config Extra configurations to tune the code scanner.
   * @param verbose - If true, all logs would be printed to console. 
   */
  constructor(
    elementId: string,
    config: Html5QrcodeScannerConfig | undefined,
    verbose: boolean | undefined) {}

  /**
   * Renders the User Interface.
   * 
   * @param qrCodeSuccessCallback Callback called when an instance of a QR
   * code or any other supported bar code is found.
   * @param qrCodeErrorCallback optional callback called in cases where no
   * instance of QR code or any other supported bar code is found.
   */
  render(
    qrCodeSuccessCallback: QrcodeSuccessCallback,
    qrCodeErrorCallback: QrcodeErrorCallback | undefined) {}

  /**
   * Pauses the ongoing scan.
   * 
   * Notes:
   * -   Should only be called if camera scan is ongoing.
   *
   * @param shouldPauseVideo (Optional, default = false) If {@code true}
   * the video will be paused.
   * 
   * @throws error if method is called when scanner is not in scanning state.
   */
  pause(shouldPauseVideo?: boolean);

  /**
   * Resumes the paused scan.
   * 
   * If the video was previously paused by setting {@code shouldPauseVideo}
   * to {@code true} in {@link Html5QrcodeScanner#pause(shouldPauseVideo)},
   * calling this method will resume the video.
   *
   * Notes:
   * -   Should only be called if camera scan is ongoing.
   * -   With this caller will start getting results in success and error
   * callbacks.
   * 
   * @throws error if method is called when scanner is not in paused state.
   */
  resume();
    
  /**
   * Gets state of the camera scan.
   *
   * @returns state of type {@enum Html5QrcodeScannerState}.
   */
  getState(): Html5QrcodeScannerState;

  /** Removes the QR Code scanner UI. */
  clear(): Promise  {}
}

Extra optional configuration in start() method

Configuration object that can be used to configure both the scanning behavior and the user interface (UI). Most of the fields have default properties that will be used unless a different value is provided. If you do not want to override anything, you can just pass in an empty object {}.

fps — Integer, Example = 10

A.K.A frame per second, the default value for this is 2, but it can be increased to get faster scanning. Increasing too high value could affect performance. Value >1000 will simply fail.

qrbox — QrDimensions or QrDimensionFunction (Optional), Example = { width: 250, height: 250 }

Use this property to limit the region of the viewfinder you want to use for scanning. The rest of the viewfinder would be shaded. For example, by passing config { qrbox : { width: 250, height: 250 } }, the screen will look like:

This can be used to set a rectangular scanning area with config like:

let config = { qrbox : { width: 400, height: 150 } }

This config also accepts a function of type

/**
  * A function that takes in the width and height of the video stream 
* and returns QrDimensions.
* 
* Viewfinder refers to the video showing camera stream.
*/
type QrDimensionFunction =
    (viewfinderWidth: number, viewfinderHeight: number) => QrDimensions;

This allows you to set dynamic QR box dimensions based on the video dimensions. See this blog article for example: Setting dynamic QR box size in Html5-qrcode - ScanApp blog

> This might be desirable for bar code scanning.

If this value is not set, no shaded QR box will be rendered and the scanner will scan the entire area of video stream.

aspectRatio — Float, Example 1.777778 for 16:9 aspect ratio

Use this property to render the video feed in a certain aspect ratio. Passing a nonstandard aspect ratio like 100000:1 could lead to the video feed not even showing up. Ideal values can be:

Value	Aspect Ratio	Use Case
1.333334	4:3	Standard camera aspect ratio
1.777778	16:9	Full screen, cinematic
1.0	1:1	Square view

If you do not pass any value, the whole viewfinder would be used for scanning. Note: this value has to be smaller than the width and height of the QR code HTML element.

disableFlip — Boolean (Optional), default = false

By default, the scanner can scan for horizontally flipped QR Codes. This also enables scanning QR code using the front camera on mobile devices which are sometimes mirrored. This is false by default and I recommend changing this only if:

• You are sure that the camera feed cannot be mirrored (Horizontally flipped)
• You are facing performance issues with this enabled.

Here's an example of a normal and mirrored QR Code

Normal QR Code	Mirrored QR Code

rememberLastUsedCamera — Boolean (Optional), default = true

If true the last camera used by the user and weather or not permission was granted would be remembered in the local storage. If the user has previously granted permissions — the request permission option in the UI will be skipped and the last selected camera would be launched automatically for scanning.

If true the library shall remember if the camera permissions were previously granted and what camera was last used. If the permissions is already granted for "camera", QR code scanning will automatically * start for previously used camera.

supportedScanTypes - Array | []

Default = [Html5QrcodeScanType.SCAN_TYPE_CAMERA, Html5QrcodeScanType.SCAN_TYPE_FILE]

This field can be used to:

• Limit support to either of Camera or File based scan.
• Change default scan type.

How to use:

function onScanSuccess(decodedText, decodedResult) {
  // handle the scanned code as you like, for example:
  console.log(`Code matched = ${decodedText}`, decodedResult);
}

let config = {
  fps: 10,
  qrbox: {width: 100, height: 100},
  rememberLastUsedCamera: true,
  // Only support camera scan type.
  supportedScanTypes: [Html5QrcodeScanType.SCAN_TYPE_CAMERA]
};

let html5QrcodeScanner = new Html5QrcodeScanner(
  "reader", config, /* verbose= */ false);
html5QrcodeScanner.render(onScanSuccess);

For file based scan only choose:

supportedScanTypes: [Html5QrcodeScanType.SCAN_TYPE_FILE]

For supporting both as it is today, you can ignore this field or set as:

supportedScanTypes: [
  Html5QrcodeScanType.SCAN_TYPE_CAMERA,
  Html5QrcodeScanType.SCAN_TYPE_FILE]

To set the file based scan as defult change the order:

supportedScanTypes: [
  Html5QrcodeScanType.SCAN_TYPE_FILE,
  Html5QrcodeScanType.SCAN_TYPE_CAMERA]

Scanning only specific formats

By default, both camera stream and image files are scanned against all the supported code formats. Both Html5QrcodeScanner and Html5Qrcode classes can be configured to only support a subset of supported formats. Supported formats are defined in enum Html5QrcodeSupportedFormats.

enum Html5QrcodeSupportedFormats {
  QR_CODE = 0,
  AZTEC,
  CODABAR,
  CODE_39,
  CODE_93,
  CODE_128,
  DATA_MATRIX,
  MAXICODE,
  ITF,
  EAN_13,
  EAN_8,
  PDF_417,
  RSS_14,
  RSS_EXPANDED,
  UPC_A,
  UPC_E,
  UPC_EAN_EXTENSION,
}

I recommend using this only if you need to explicitly omit support for certain formats or want to reduce the number of scans done per second for performance reasons.

Scanning only QR code with Html5Qrcode

const html5QrCode = new Html5Qrcode(
  "reader", { formatsToSupport: [ Html5QrcodeSupportedFormats.QR_CODE ] });
const qrCodeSuccessCallback = (decodedText, decodedResult) => {
    /* handle success */
};
const config = { fps: 10, qrbox: { width: 250, height: 250 } };

// If you want to prefer front camera
html5QrCode.start({ facingMode: "user" }, config, qrCodeSuccessCallback);

Scanning only QR code and UPC codes with Html5QrcodeScanner

function onScanSuccess(decodedText, decodedResult) {
  // Handle the scanned code as you like, for example:
  console.log(`Code matched = ${decodedText}`, decodedResult);
}

const formatsToSupport = [
  Html5QrcodeSupportedFormats.QR_CODE,
  Html5QrcodeSupportedFormats.UPC_A,
  Html5QrcodeSupportedFormats.UPC_E,
  Html5QrcodeSupportedFormats.UPC_EAN_EXTENSION,
];
const html5QrcodeScanner = new Html5QrcodeScanner(
  "reader",
  {
    fps: 10,
    qrbox: { width: 250, height: 250 },
    formatsToSupport: formatsToSupport
  },
  /* verbose= */ false);
html5QrcodeScanner.render(onScanSuccess);

Experimental features

The library now supports some experimental features which are supported in the library but not recommended for production usage either due to limited testing done or limited compatibility for underlying APIs used. Read more about it here. Some experimental features include:

• Support for BarcodeDetector JavaScript API

How to modify and build

1. Code changes should only be made to /src only.

2. Run npm install to install all dependencies.

3. Run npm run-script build to build JavaScript output. The output JavaScript distribution is built to /dist/html5-qrcode.min.js. If you are developing on Windows OS, run npm run-script build-windows.

4. Testing

   • Run npm test
   • Run the tests before sending a pull request, all tests should run.
   • Please add tests for new behaviors sent in PR.

5. Send a pull request

   • Include code changes only to ./src. Do not change ./dist manually.
   • In the pull request add a comment like

   @all-contributors please add @mebjas for this new feature or tests
   

   • For calling out your contributions, the bot will update the contributions file.
   • Code will be built & published by the author in batches.

How to contribute

You can contribute to the project in several ways:

• File issue ticket for any observed bug or compatibility issue with the project.
• File feature request for missing features.
• Take open bugs or feature request and work on it and send a Pull Request.
• Write unit tests for existing codebase (which is not covered by tests today). Help wanted on this - read more.

Support 💖

This project would not be possible without all of our fantastic contributors and sponsors. If you'd like to support the maintenance and upkeep of this project you can donate via GitHub Sponsors.

And huge thanks to following organizations for non monitery sponsorships

Credits

The decoder used for the QR code reading is from Zxing-js https://github.com/zxing-js/library