This one looks nice. According with their own description:
Using Lazar Laszlo's port of ZXing Java library, QCodeDecoder brings
to the web a great interface for dealing with QRCode decoding, being
usable both on desktops and mobile phones.
Demo: http://cirocosta.github.io/qcode-decoder/
Repository: https://github.com/cirocosta/qcode-decoder
