About
“A QR code (abbreviation for Quick Response code) is a specific matrix barcode (or two-dimensional code) that is readable by dedicated QR barcode readers and camera telephones. The code consists of black modules arranged in a square pattern on a white background. The information encoded may be text, URL, or other data.” (Wikipedia)
This site provides a QR Code scanner directly in the browser, implemented in JavaScript.
Supported browsers: 
or 
or 
Unlike other products, this solution provides an easier way to read QR Codes as no image uploading is necessary.
The JavaScript implementation is based on the ZXing multi-format 1D/2D barcode image processing library implemented in Java.
The QR Codes are created with the Google Chart Tools.
The source code of the QR Code scanner is on GitHub (https://github.com/LazarSoft/jsqrcode).