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Swift
Objective-C

Barcode Reader for Your Website

Dynamsoft Barcode Reader JavaScript Edition is equipped with industry-leading algorithms for exceptional speed, accuracy and read rates in barcode reading. With its well-designed API, you can turn your web page into a barcode scanner with just a few lines of code.

version downloads jsdelivr vulnerabilities

Once integrated, your users can open your website in a browser, access their cameras and read barcodes directly from the video input.

In this guide, you will learn step by step on how to integrate this library into your website.

Table of Contents

Popular Examples

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Hello World - Simplest Implementation

Let’s start with the “Hello World” example of the library which demonstrates how to use the minimum code to enable a web page to read barcodes from a live video stream.

Step One: Check the code of the example

The complete code of the “Hello World” example is shown below

<!DOCTYPE html>
<html>

<body>
    <script src="https://cdn.jsdelivr.net/npm/dynamsoft-javascript-barcode@9.0.0/dist/dbr.js"></script>
  <script>
        // Specifies a license, you can visit https://www.dynamsoft.com/customer/license/trialLicense?utm_source=guide&product=dbr&package=js to get your own trial license good for 30 days. 
        Dynamsoft.DBR.BarcodeScanner.license = 'DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9';
        // Initializes and uses the library
        (async () => {
            let scanner = await Dynamsoft.DBR.BarcodeScanner.createInstance();
            scanner.onFrameRead = results => {
                if (results.length > 0) console.log(results);
            };
            scanner.onUniqueRead = (txt, result) => {
                alert(txt);
            };
            await scanner.show();
        })();
    </script>
</body>

</html>

Code in Github   Run via JSFiddle   Run in Dynamsoft   Download from Dynamsoft

About the code

  • license: This property specifies a license key. Read more on Specify the license.

  • createInstance(): This method creates a BarcodeScanner object. This object can read barcodes directly from a video input with the help of its interactive UI (hidden by default) and the MediaDevices interface.

  • onFrameRead: This event is triggered every time the library finishes scanning a video frame. The results object contains all the barcode results that the library have found on this frame. In this example, we print the results to the browser console.

  • onUniqueRead: This event is triggered when the library finds a new barcode, which is not a duplicate among multiple frames. txt holds the barcode text value while result is an object that holds details of the barcode. In this example, an alert will be displayed for this new barcode.

  • show(): This method brings up the built-in UI of the BarcodeScanner object and starts scanning.

Step Two: Test the example

Open the example page in a browser, allow the page to access your camera and the video will show up on the page. After that, you can point the camera at a barcode to read it.

When a barcode is decoded, you will see the result text pop up and the barcode location will be highlighted in the video feed.

Note:

  • Although the page should work properly when opened directly as a file (“file:///”), it’s recommended that you deploy it to a web server before accessing it. Also, some browsers require a secure connection (HTTPS) to access the cameras, so deploying the page to a HTTPS website is the best choice.
  • For first use, you may need to wait a few seconds for the library to initialize.
  • The license “DLS2eyJvcmdhbml6YXRpb25JRCI6IjIwMDAwMSJ9” used in this sample is an online license and requires network connection to work.

If the test doesn’t go as expected, you can check out the FAQ or contact us.

Building your own page

Include the library

Use a CDN

The simplest way to include the library is to use either the jsDelivr or UNPKG CDN. The “hello world” example above uses jsDelivr.

  • jsDelivr

    <script src="https://cdn.jsdelivr.net/npm/dynamsoft-javascript-barcode@9.0.0/dist/dbr.js"></script>

  • UNPKG

    <script src="https://unpkg.com/dynamsoft-javascript-barcode@9.0.0/dist/dbr.js"></script>

Host the library yourself

Besides using the CDN, you can also download the library and host its files on your own website / server before including it in your application.

To download the library:

  • yarn

    yarn add dynamsoft-javascript-barcode

  • npm

    npm install dynamsoft-javascript-barcode --save

Depending on how you downloaded the library and where you put it, you can typically include it like this:

<script src="/dbr-js-9.0.0/dist/dbr.js"></script>

or

<script src="/node_modules/dynamsoft-javascript-barcode/dist/dbr.js"></script>

Read more on how to host the library.

Configure the library

Before using the library, you need to configure a few things.

Specify the license

The library requires a license to work, use the API license to specify a license key.

Dynamsoft.DBR.BarcodeScanner.license = "YOUR-LICENSE-KEY";

To test the library, you can request a 30-day trial license via the Request a Trial License link.

If you registered for a Dynamsoft account and downloaded the library from the official site, Dynamsoft will generate a 30-day trial license for you and put the license key in all the downloaded samples.

Specify the location of the “engine” files

If the engine files (*.worker.js, *.wasm.js and *.wasm, etc.) are not in the same location with the main library file (dbr.js), you can use the API engineResourcePath to specify the engine path, for example:

//The following code uses the jsDelivr CDN, feel free to change it to your own location of these files
Dynamsoft.DBR.BarcodeScanner.engineResourcePath = "https://cdn.jsdelivr.net/npm/dynamsoft-javascript-barcode@9.0.0/dist/";

This configuration is usually required with frameworks like Angular or React where dbr.js is compiled into another file.

Interact with the library

Create a BarcodeScanner object

You can use one of two classes ( BarcodeScanner and BarcodeReader ) to interact with the library. BarcodeReader is a low-level class that processes images directly. BarcodeScanner, on the other hand, inherits from BarcodeReader and provides high-level APIs and a built-in GUI to allow continuous barcode scanning on video frames. We’ll focus on BarcodeScanner in this guide.

To use the library, we first create a BarcodeScanner object.

Dynamsoft.DBR.BarcodeScanner.license = "YOUR-LICENSE-KEY";
let scanner = null;
try {
    scanner = await Dynamsoft.DBR.BarcodeScanner.createInstance();
} catch (ex) {
    console.error(ex);
}

Tip: When creating a BarcodeScanner object within a function which may be called more than once, it’s best to use a “helper” variable to avoid double creation such as pScanner in the following code

Dynamsoft.DBR.BarcodeScanner.license = "YOUR-LICENSE-KEY";
let pScanner = null;
document.getElementById('btn-scan').addEventListener('click', async () => {
    try {
        const scanner = await (pScanner = pScanner || Dynamsoft.DBR.BarcodeScanner.createInstance());
    } catch (ex) {
        console.error(ex);
    }
});

Configure the BarcodeScanner object

Let’s take a look at the following code snippets:

// set which camera and what resolution to use
let allCameras = await scanner.getAllCameras();
await scanner.setCurrentCamera(allCameras[0].deviceId);
await scanner.setResolution(1280, 720);

// set up the scanner behavior
let scanSettings = await scanner.getScanSettings();
// disregard duplicated results found in a specified time period (in milliseconds)
scanSettings.duplicateForgetTime = 5000;
// set a scan interval in milliseconds so the library may release the CPU from time to time
// setting this value larger is also a simple way to save battery power and reduce device heating.
scanSettings.intervalTime = 100;
await scanner.updateScanSettings(scanSettings);

// use one of the built-in RuntimeSetting templates: "single" (decode a single barcode, the default mode), "speed", "balance" and "coverage"
await scanner.updateRuntimeSettings("speed");

// make changes to the template. The code below demonstrates how to specify enabled symbologies
let runtimeSettings = await scanner.getRuntimeSettings();
runtimeSettings.barcodeFormatIds = Dynamsoft.DBR.EnumBarcodeFormat.BF_ONED | Dynamsoft.DBR.EnumBarcodeFormat.BF_QR_CODE;
await scanner.updateRuntimeSettings(runtimeSettings);

Try in JSFiddle

As you can see from the above code snippets, there are three types of configurations:

  • get/updateVideoSettings: Configures the data source, i.e., the camera. These settings include which camera to use, the resolution, etc. Learn more here.

  • get/updateScanSettings: Configures the behavior of the scanner which includes duplicateForgetTime and intervalTime, etc.

  • get/updateRuntimeSettings: Configures the decode engine with either a built-in template or a comprehensive RuntimeSettings object. For example, the following uses the built-in “speed” settings with updated localizationModes.

Find the full list of the runtime settings here.

  await barcodeScanner.updateRuntimeSettings("speed");
  //await barcodeScanner.updateRuntimeSettings("balance"); //alternative
  //await barcodeScanner.updateRuntimeSettings("coverage"); //alternative
  let settings = await barcodeScanner.getRuntimeSettings();
  settings.localizationModes = [
      Dynamsoft.DBR.EnumLocalizationMode.LM_CONNECTED_BLOCKS,
      Dynamsoft.DBR.EnumLocalizationMode.LM_SCAN_DIRECTLY,
      Dynamsoft.DBR.EnumLocalizationMode.LM_LINES, 0, 0, 0, 0, 0
  ];
  await barcodeScanner.updateRuntimeSettings(settings);

Try in JSFiddle.

See also settings samples.

Customize the UI

The built-in UI of the BarcodeScanner object is defined in the file dist/dbr.ui.html . There are a few ways to customize it:

  • Modify the file dist/dbr.ui.html directly.

    This option is only possible when you host this file on your own web server instead of using a CDN.

  • Copy the file dist/dbr.ui.html to your application, modify it and use the the API defaultUIElementURL to set it as the default UI.

    Dynamsoft.DBR.BarcodeScanner.defaultUIElementURL = "THE-URL-TO-THE-FILE";

    You must set defaultUIElementURL before you call createInstance() .

  • Append the default UI element to your page, customize it before showing it.

    <div id="div-ui-container"></div>

    document.getElementById('div-ui-container').appendChild(scanner.getUIElement());
document.getElementsByClassName('dce-btn-close')[0].hidden = true; // Hide the close button

  • Build the UI element into your own web page and specify it with the API setUIElement(HTMLElement).

    • Embed the video

      <div id="div-ui-container" style="width:100%;height:100%;">
    <div class="dce-video-container" style="position:relative;width:100%;height:500px;"></div>
</div>
<script>
    (async () => {
        let scanner = await Dynamsoft.DBR.BarcodeScanner.createInstance();
        await scanner.setUIElement(document.getElementById('div-ui-container'));
        scanner.onFrameRead = results => {
            console.log(results);
        };
        scanner.onUniqueRead = (txt, result) => {
            alert(txt);
        };
        await scanner.show();
    })();
</script>

      The video element will be created and appended to the DIV element with the class dce-video-container, make sure the class name is the same. Besides, the CSS property position of the DIV element must be either relative, absolute, fixed, or sticky.

      Try in JSFiddle

    • Add the camera list and resolution list

      If the class names for these lists match the default ones, dce-sel-camera and dce-sel-resolution , the library will automatically populate the lists and handle the camera/resolution switching.

      <select class="dce-sel-camera"></select>

      Try in JSFiddle

      <select class="dce-sel-resolution"></select>

      Try in JSFiddle

      By default, 8 hard-coded resolutions are populated as options. You can show only a custom set of options by hardcoding them.

      <select class="dce-sel-resolution">
    <option class="dce-opt-gotResolution" value="got"></option>
    <option data-width="1920" data-height="1080">1920 x 1080</option>
    <option data-width="1280" data-height="720">1280 x 720</option>
    <option data-width="640" data-height="480">640 x 480</option>
</select>

      Try in JSFiddle

      Generally, you need to provide a resolution that the camera supports. However, in case a camera does not support the specified resolution, it usually uses the nearest supported resolution. As a result, the selected resolution may not be the actual resolution used. In this case, add an option with the class name dce-opt-gotResolution (as shown above) and the library will then use it to show the actual resolution.

See also UI customization samples.

API Documentation

You can check out the detailed documentation about the APIs of the library at https://www.dynamsoft.com/barcode-reader/programming/javascript/api-reference/?ver=9.0.0.

System Requirements

This library requires the following features which are supported by all modern mainstream browsers:

  • WebAssembly, Blob, URL/createObjectURL, Web Workers

    The above four features are required for the library to work.

  • MediaDevices/getUserMedia

    This API is only required for in-browser video streaming. If a browser does not support this API, the Single Frame Mode will be used automatically. If the API exists but doesn’t work correctly, the Single Frame Mode can be used as an alternative way to access the camera.

  • getSettings

    This API inspects the video input which is a MediaStreamTrack object about its constrainable properties.

The following table is a list of supported browsers based on the above requirements:

Browser Name Version
Chrome v59+1
Firefox v52+ (v55+ on Android/iOS1)
Edge2 v16+
Safari3 v11+

1 iOS 14.3+ is required for camera video streaming in Chrome and Firefox or Apps using webviews.

2 On Edge, due to strict Same-origin policy, you must host the library files on the same domain as your web page.

3 Safari 11.2.2 ~ 11.2.6 are not supported.

Apart from the browsers, the operating systems may impose some limitations of their own that could restrict the use of the library. Browser compatibility ultimately depends on whether the browser on that particular operating system supports the features listed above.

Advanced Usage

In addition to the above basic settings, the library has many more settings and options that you can adjust to best suit your usage. To read more, please see advanced usage.

How to Upgrade

If you want to upgrade the library from an old version to a newer one, please see how to upgrade.

FAQ

Can I open the web page directly from the hard drive?

Yes, for simple testing purposes, it’s perfectly fine to open the file directly from the hard drive. However, you might encounter some issues in doing so (like unable to access the camera, etc.). The recommendation is to deploy this page to your web server and run it over HTTPS. If you don’t have a ready-to-use web server but have a package manager like npm or yarn, you can set up a simple HTTP server in minutes. Check out http-server on npm.

Why can’t I use my camera?

If you open the web page as file:/// or http:// , the camera may not work and you see the following error in the browser console:

[Deprecation] getUserMedia() no longer works on insecure origins. To use this feature, you should consider switching your application to a secure origin, such as HTTPS. See https://goo.gl/rStTGz for more details.

In Safari 12 the equivalent error is:

Trying to call getUserMedia from an insecure document.

You get this error because the API getUserMedia requires HTTPS to access the camera.

To make sure your web application can access the camera, please configure your web server to support HTTPS. The following links may help.

  1. NGINX: Configuring HTTPS servers
  2. IIS: Create a Self Signed Certificate in IIS
  3. Tomcat: Setting Up SSL on Tomcat in 5 minutes
  4. Node.js: npm tls

If you use Chrome or Firefox, you might not get the error because these two browsers allow camera access via file:/// and http://localhost. However, our recommendation is that you deploy the web page to a web server that supports HTTPS.

Accounting for newline characters in the barcode result

When it comes to HTML, newline characters ( \n ) are not interpreted as they normally would. Therefore, if a barcode result contains a newline character, and you display the result in an modal dialogue box or some other text elements, then the newline character will probably be ignored.

There are two ways in which you can resolve this:

  1. Wrap the element used to display the result in a <pre> element.
  2. Manually replace each \n character in the result with <br>

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