Access Camera And Read Qr Code Using Javascript
QR codes or quick response codes are getting more and more popular every passing day. They can be found everywhere in modern life, from ticketing, packaging, advertising to mobile payments, and many others. A QR code is a two-dimensional barcode that can store a considerable amount of information such as URLs, email addresses, phone numbers, or business cards. Users can scan a QR code using their smartphone camera or any other compatible device and get the encoded data immediately.
JavaScript is a popular scripting language that is widely used for web development. It is a high-level, dynamic, and interpreted language that can run on almost any browser. It has many features that make it an excellent choice for web developers such as the ability to manipulate DOM elements, control animations, and handle data in many formats. In this article, we will discuss how to access the camera and read QR code using JavaScript.
What is the QR code scanner?
The QR code scanner is a web application that allows users to access the camera and scan QR codes. The scanner works by capturing a video stream from the camera and then processing the frames to detect any QR code. Once a QR code is detected, the scanner decodes the information and shows it to the user. The scanner allows users to interact with the web application in new and exciting ways.
How to access the camera using JavaScript?
JavaScript provides the MediaDevices API that allows web applications to access multimedia devices such as cameras, microphones, or speakers. The API provides two methods, getUserMedia() and enumerateDevices(), that can be used to access the camera.
The getUserMedia() method is used to request access to the camera. It returns a promise that resolves with a MediaStream object that represents the video stream from the camera. The MediaStream object can then be used as the source of a video element or to process the frames.
The enumerateDevices() method is used to list all the available multimedia devices on the user's machine. It returns a promise that resolves with an array of MediaDeviceInfo objects that contain information about the devices such as their id, label, and type.
How to read QR code using JavaScript?
There are many libraries available that can be used to read QR code using JavaScript. The most popular libraries are jsQR and ZXing. Both libraries are open source and can be easily integrated into any web application.
The jsQR library is a pure JavaScript implementation of the QR code decoder. It is lightweight, fast, and easy to use. To use the library, you need to pass the image data as an array buffer to the decode() method. The method then returns the decoded string if a QR code is detected. If no QR code is detected, it returns null.
The ZXing library is a more sophisticated library that supports the decoding of many other types of barcodes as well as QR codes. It is written in Java and has been ported to many other languages including JavaScript. The library can be easily integrated into any web application using the JavaScript port. To use the library, you need to pass the image data as a canvas element to the decode() method. The method then returns the decoded result if a barcode or QR code is detected. If no barcode or QR code is detected, it returns null.
Conclusion
In conclusion, accessing the camera and reading QR code using JavaScript can be a daunting task. However, with the help of the MediaDevices API and libraries such as jsQR and ZXing, it becomes a manageable task that can be easily integrated into web applications. We hope that this article has provided you with an insightful overview of how to access the camera and read QR code using JavaScript.
