JavaScript itself cannot natively generate or decode QR codes without external libraries or APIs. However, you can use JavaScript libraries to achieve both tasks:

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1. Generating QR Codes in JavaScript

Several JavaScript libraries allow you to generate QR codes dynamically. The most popular ones are:

• qrcode.js (Pure JavaScript)
• QRCode.js (Lightweight)
• node-qrcode (For Node.js)

Example (using qrcode.js):

html
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<div id="qrcode"></div>
<script src="https://cdn.jsdelivr.net/npm/qrcode@1.5.1/build/qrcode.min.js"></script>
<script>
  new QRCode(document.getElementById("qrcode"), {
    text: "https://example.com",
    width: 128,
    height: 128,
  });
</script>

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2. Reading QR Codes in JavaScript

To read QR codes from images or camera input, you need libraries that use the device's camera or process images:

• ZXing (Zebra Crossing) (Supports both decoding and encoding)
• QuaggaJS (For camera-based scanning)
• Instascan (For browser-based scanning)

Example (using ZXing):

html
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<video id="preview"></video>
<script src="https://cdn.jsdelivr.net/npm/@zxing/library@latest"></script>
<script>
  const codeReader = new ZXing.BrowserQRCodeReader();
  codeReader.decodeFromVideoDevice(null, 'preview', (result, err) => {
    if (result) console.log("QR Code:", result);
  });
</script>

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Summary Table

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