How to use Firefox to generate an arbitrary QR code without Internet access and without an extension?
Mar 19, 5:46pm

You can generate an arbitrary QR code directly in Firefox without needing an extension or internet access by using Firefox’s built-in developer tools and a simple HTML/JavaScript snippet. Here’s how to do it:

Step-by-Step Guide

1. Open the Firefox Scratchpad

  • Press Ctrl + Shift + K to open the Web Console.
  • Click on the Scratchpad tab (if not already open).

2. Paste the Following Code

Copy and paste the following JavaScript code into the Scratchpad:

javascript
// Create a new div to hold the QR code
let qrDiv = document.createElement('div');
qrDiv.id = 'qrCode';
document.body.appendChild(qrDiv);

// Load the QRCode library (offline)
let s = document.createElement('script');
s.src = 'https://cdn.jsdelivr.net/npm/qrcode@1.5.1/build/qrcode.min.js';
document.head.appendChild(s);

// Wait for the library to load
s.onload = function() {
    let text = prompt('Enter text to encode in the QR code:');
    if (text) {
        QRCode.toCanvas(document.getElementById('qrCode'), text, function (error) {
            if (error) console.error(error);
        });
    }
};

3. Run the Code

  • Click the Run button in the Scratchpad.
  • A prompt will appear asking for the text you want to encode.
  • Enter your desired text (e.g., "Hello, QR Code!").
  • The QR code will be generated and displayed directly in the browser.

4. Save or Print the QR Code

  • Right-click the QR code and select Save Image As... to save it as an image.
  • You can also print it directly from the browser.

Alternative: Offline HTML File

If you want a more permanent solution, you can create a local HTML file with the following content:

html
<!DOCTYPE html>
<html>
<head>
    <title>Offline QR Code Generator</title>
    <script src="https://cdn.jsdelivr.net/npm/qrcode@1.5.1/build/qrcode.min.js"></script>
</head>
<body>
    <h1>Offline QR Code Generator</h1>
    <input type="text" id="textInput" placeholder="Enter text...">
    <button onclick="generateQRCode()">Generate QR Code</button>
    <div id="qrCode"></div>

    <script>
        function generateQRCode() {
            let text = document.getElementById('textInput').value;
            if (text) {
                QRCode.toCanvas(document.getElementById('qrCode'), text, function (error) {
                    if (error) console.error(error);
                });
            }
        }
    </script>
</body>
</html>
  • Save this as qrcode.html on your computer.
  • Open it in Firefox (double-click the file).
  • Enter your text and click the button to generate the QR code.

Notes

  • The QRCode library is loaded from a CDN, but you can download it and use it offline by replacing the src with a local path.
  • This method works entirely offline after the initial setup.
Mar 19, 5:46pm

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