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Building a QR Code Generator with JavaScript


QR codes, short for Quick Response codes, have become increasingly popular in web applications due to their ability to quickly and efficiently store information. These square-shaped codes can be scanned by smartphones and other devices equipped with QR code readers, allowing users to access websites, download apps, or retrieve information with just a scan.

In this article, we will explore the process of generating QR codes using JavaScript. We will cover the basics of QR code generation and discuss how JavaScript can be leveraged to create dynamic QR codes based on user input. So let's dive in and discover the power of QR code generation with JavaScript.

Getting Started

Before we can start building our QR code generator with JavaScript, we need to set up our development environment and include the necessary JavaScript libraries for generating QR codes.

Setting up the development environment

To get started, you'll need a text editor or integrated development environment (IDE) of your choice. Popular options include Visual Studio Code, Sublime Text, and Atom. Choose the one that you are most comfortable with.

You'll also need a web browser to test and view your QR codes. Any modern browser such as Google Chrome, Mozilla Firefox, or Safari will work.

Including necessary JavaScript libraries for generating QR codes

To generate QR codes in JavaScript, we'll use a third-party library. There are several libraries available, each with their own features and capabilities. Two popular libraries are qrcode.js and jquery-qrcode.


qrcode.js is a lightweight library that allows you to generate QR codes without any dependencies. To include qrcode.js in your project, you can either download the library from the official website and include it in your HTML file, or you can use a package manager like npm or yarn to install it.

<script src="path/to/qrcode.min.js"></script>


jquery-qrcode is a jQuery plugin that provides an easy way to generate QR codes using jQuery. To include jquery-qrcode in your project, you'll need to include both jQuery and the jquery-qrcode library. You can either download the libraries and include them in your HTML file, or you can use a CDN.

<script src="path/to/jquery.min.js"></script>
<script src="path/to/jquery.qrcode.min.js"></script>

Once you have included the necessary libraries, you are ready to start generating QR codes with JavaScript. In the next section, we will explore the basic algorithm for generating QR codes and implement it in JavaScript.

Basic QR Code Generation

QR code generation involves encoding data into a matrix of black and white squares that can be scanned and read by QR code readers. The process of generating QR codes can be broken down into a series of steps:

  1. Data Encoding: The first step in generating a QR code is to encode the data that will be stored in the code. This can include various types of information such as URLs, text, contact information, or even Wi-Fi network configurations.

  2. Error Correction: To ensure the reliability of the QR code, error correction techniques are applied. This allows the code to still be scanned and read accurately even if some parts of it are damaged or obscured.

  3. Module Placement: The encoded data is then converted into a matrix of black and white modules. These modules represent the individual squares that make up the QR code. The position and arrangement of these modules follow specific patterns and rules.

  4. Masking: To improve the readability of the code, a masking process is applied. This involves changing the color of certain modules based on predefined patterns. The purpose of masking is to reduce visual artifacts and make the code easier to scan.

  5. Format Encoding: The QR code also includes encoding for format information such as the version of the code and the error correction level used. This allows QR code readers to interpret the code correctly.

Implementing the QR code generation algorithm in JavaScript can be done using various libraries and APIs available. One popular library is 'qrcode-generator', which provides a simple and straightforward way to generate QR codes. Here's an example of how to use this library:

// Include the qrcode-generator library
<script src="qrcode-generator.js"></script>

// Create a new QRCode instance
var qr = new QRCode(document.getElementById("qrcode"), {
  text: "",
  width: 128,
  height: 128

// Generate the QR code

In this example, we create a new QRCode instance and pass in the element ID of the HTML element where the QR code will be displayed. We also provide the text to be encoded and the desired width and height of the QR code. Finally, we call the make() method to generate the QR code.

By exploring and implementing a simple algorithm for generating QR codes in JavaScript, we can easily add QR code generation functionality to our web applications. This allows users to encode and share information in a visually appealing and scannable format.

QR Code Generation based on User Input

In order to create a QR code generator that is based on user input, we need to create an input form where users can enter the content they want to encode. This can be done using HTML and JavaScript.

First, let's create an HTML form element that includes an input field and a button for generating the QR code:

<form id="qr-form">
  <input type="text" id="content-input" placeholder="Enter content">
  <button type="submit">Generate QR Code</button>

Next, we need to write JavaScript code to handle the form submission and generate the QR code dynamically. We can use an event listener to listen for the form submission and prevent the default behavior:

document.getElementById("qr-form").addEventListener("submit", function(event) {
  event.preventDefault(); // Prevent form submission

  // Get user input
  var content = document.getElementById("content-input").value;

  // Generate QR code using a QR code generation library
  var qrCode = generateQRCode(content);

  // Display the QR code on the page

In the JavaScript code above, we use the addEventListener method to listen for the "submit" event on the form element with the ID "qr-form". Inside the event listener, we prevent the default form submission behavior using event.preventDefault(). We then retrieve the user input from the input field with the ID "content-input" using document.getElementById("content-input").value.

After obtaining the user input, we can generate the QR code using a QR code generation library. There are several JavaScript libraries available for QR code generation, such as qrcode.js and qr-image. You can choose the library that best fits your needs.

Finally, we can display the generated QR code on the page by calling the displayQRCode function, passing the generated QR code as an argument. The displayQRCode function can be implemented using HTML and CSS to render the QR code on the page.

By following these steps, you can create a QR code generator that allows users to input their desired content and dynamically generate QR codes based on their input. This can be a useful feature for applications that require on-the-fly QR code generation, such as ticketing systems, inventory management, or contact information sharing.

Advanced Techniques for QR Code Generation

When it comes to generating QR codes with JavaScript, there are several third-party libraries available that offer more advanced features and options. These libraries provide additional customization options and support for different types of content that can be encoded into QR codes.

One popular library is qrcode.js. It is a lightweight JavaScript library that allows you to generate QR codes with various customization options. With qrcode.js, you can control the size, color, and error correction level of the QR code. It also supports encoding different types of data, such as URLs, text, email addresses, and more.

Another powerful library is jsQR. Unlike qrcode.js, jsQR is primarily designed for decoding QR codes, but it also has the ability to generate QR codes. It provides a fast and efficient QR code generation algorithm and supports multiple output formats, including SVG, PNG, and Canvas.

When choosing the best library for your project, consider the following factors:

  1. Ease of use: Look for a library that provides a simple and intuitive API for generating QR codes. Consider how easy it is to integrate the library into your existing codebase.

  2. Customization options: Evaluate the library's customization options and determine if they meet your specific requirements. Consider factors such as the ability to control the size, color, and error correction level of the QR code.

  3. Performance: Consider the library's performance in terms of speed and efficiency. Generating QR codes can be computationally intensive, especially for large amounts of data. Choose a library that offers good performance without compromising accuracy.

  4. Compatibility: Check if the library is compatible with the browsers and devices you are targeting. Ensure that it works well across different platforms to provide a consistent experience for your users.

Before making a decision, it's a good idea to test and compare different libraries to see which one best fits your needs. Consider factors such as ease of use, customization options, performance, and compatibility. By choosing the right library, you can leverage advanced techniques for QR code generation in your web application.

Integration with Web Applications

To integrate the QR code generation functionality into a web application, you need to follow a few steps.

Firstly, you need to include the necessary JavaScript libraries for generating QR codes in your web application. There are various libraries available, such as qrcode.js, qr.js, and jquery.qrcode. Choose the library that best suits your needs and include it in your project.

Next, you need to create a user interface element, such as a button or an input field, to trigger the QR code generation process. This can be done using HTML and CSS. When the user interacts with this element, you can capture the necessary data or input from the user.

Once you have captured the required data, you can pass it to the QR code generation function provided by the library you are using. This function will generate the QR code based on the input data. You can then display the generated QR code to the user using HTML and CSS.

There are several potential use cases for integrating QR code generation into a web application. For example, you can use QR codes to generate tickets or passes for events, to provide quick access to website URLs or app download links, or to facilitate contactless payments.

The benefits of integrating QR code generation into a web application include improved user experience, increased convenience, and enhanced security. QR codes provide a quick and easy way for users to access information or perform actions without the need for typing or manual input. They can also be encrypted or password protected to ensure the security of sensitive data.

By adding the QR code generation functionality to your web application, you can enhance its functionality and provide users with a more seamless and efficient experience.


In this article, we explored the process of building a QR code generator with JavaScript. We started by understanding the basics of QR codes and their uses in web applications. Then, we learned how to set up the development environment and include the necessary JavaScript libraries for generating QR codes.

We discussed a simple algorithm for generating QR codes and implemented it in JavaScript. We also explored the option of dynamically generating QR codes based on user input by creating an input form.

Additionally, we delved into more advanced techniques for QR code generation, such as using third-party JavaScript libraries that offer additional features and customization options. We compared different libraries and encouraged readers to choose the one that best fits their project requirements.

Finally, we discussed the integration of QR code generation functionality into web applications and highlighted potential use cases and benefits.

Overall, building a QR code generator with JavaScript can be a valuable addition to any web application. It provides a convenient way to share information with users and opens up possibilities for various use cases. We encourage readers to implement a QR code generator in their own web applications to enhance user experience and streamline information sharing.