Read and Generate QR codes in js - either in node, or in the browser with browserify.
A fork of jsqrcode which is a port of ZXing
Set qrcode.callback to function "func(data)", where data will get the decoded information.
Decode image with: qrcode.decode(url or DataURL). Decode from canvas with "qr-canvas" ID: qrcode.decode()
For webcam qrcode decoding (included in the test.html) you will need the camcanvas.swf from http://www.taboca.com/p/camcanvas/