Generate and Use QRCode

QR Codes, or Quick Response Codes, are two-dimensional barcodes that are used to store and transmit information. They are commonly used in advertising, packaging, and electronic ticketing, and are a convenient way to share information quickly and easily.

To use QR Codes in your own projects, you'll need a QR Code library or generator. There are several options available, including browser-based libraries like qrcodejs and jsQR, and server-side libraries like qrcode and python-qrcode.

In this post, we'll take a look at how to use the qrcodejs library to generate QR Codes in a web browser.

First, you'll need to include the qrcodejs library in your HTML file. You can either download the library and link to it locally, or link to the library on a CDN like unpkg:

<script src="https://unpkg.com/qrcodejs@2.0.0/qrcode.min.js"></script>

Next, you'll need to create a container element in your HTML file where the QR Code will be displayed. This could be a div, span, or any other element that you want to use:

<div id="qr-code"></div>

Now, you can use the QRCode constructor from the qrcodejs library to create a new QR Code object. This object has several options that you can use to customize the appearance and behavior of the QR Code.

Here's an example of how to create a QR Code object and customize some of its options:

const qrCode = new QRCode("qr-code", {   
    text: "https://example.com",   
    width: 128,   
    height: 128,   
    colorDark: "#000000",   
    colorLight: "#ffffff",   
    correctLevel: QRCode.CorrectLevel.H 
});

The text option is the most important one, as it specifies the data that will be encoded in the QR Code. You can use any type of data that you want, including text, URLs, and even binary data.

The width and height options specify the size of the QR Code, in pixels. You can set these values to whatever you like, but keep in mind that larger QR Codes are easier to scan, but may be more difficult to display on small screens.

The colorDark and colorLight options specify the colors that will be used for the dark and light areas of the QR Code. You can use any CSS color value here, including hex codes, RGB values, and color names.

The correctLevel option specifies the error correction level of the QR Code. This determines how much data can be recovered if the QR Code is damaged or distorted. The higher the error correction level, the more data can be recovered, but the QR Code will also be larger.

Once you've created a QR Code object and customized its options, you can use the makeCode method to generate the QR Code. This method takes the data from the text option and creates the QR Code image.

Here's an example of how to generate a QR Code:

qrCode.makeCode();

That's all you need to do to generate a QR Code using the qrcodejs library. You can customize the appearance and

behavior of the QR Code further by using additional options and methods provided by the library.

For example, you can use the clear method to clear the QR Code and remove it from the screen:

qrCode.clear();

You can also use the onRender and onClear options to specify callback functions that will be called when the QR Code is rendered or cleared. This can be useful if you want to perform additional actions when these events occur:

const qrCode = new QRCode("qr-code", {   
    text: "https://example.com",   
    width: 128,   
    height: 128,   
    colorDark: "#000000",   
    colorLight: "#ffffff",   
    correctLevel: QRCode.CorrectLevel.H,   
    onRender: function() {     
            console.log("QR Code rendered!");   
        },   
    onClear: function() {     
            console.log("QR Code cleared!");   
        } 
    });

You can also use the download method to download the QR Code as an image file. This method takes a file name as an argument, and prompts the user to download the QR Code as a PNG file:

qrCode.download("qr-code.png");

Finally, you can use the setOptions method to change the options of the QR Code after it has been created. This can be useful if you want to update the QR Code based on user input or other changes:

qrCode.setOptions({   
    text: "https://new-example.com",   
    colorDark: "#ffffff",   
    colorLight: "#000000" 
}); 
qrCode.makeCode();

In conclusion, QR Codes are a convenient way to share information quickly and easily, and the qrcodejs library makes it easy to generate QR Codes in a web browser. Whether you're working on a marketing campaign, a ticketing system, or any other project, you should be able to use QR Codes to your advantage.