It's worth adding that, in addition to the QR codes library posted by @abaumg, Google provides a QR Codes API QR Codes APImany thanks to @Toukakoukan for the link update.
To use this , basically:
https://chart.googleapis.com/chart?chs=300x300&cht=qr&chl=http%3A%2F%2Fwww.google.com%2F&choe=UTF-8
300x300
is the size of the QR image you want to generate,chl
is the url-encoded string you want to change into a QR code, andchoe
is the (optional) encoding.The link, above, gives more detail, but to use it just have the src
of an image point to the manipulated value, like so:
<img src="https://chart.googleapis.com/chart?chs=300x300&cht=qr&chl=http%3A%2F%2Fwww.google.com%2F&choe=UTF-8" title="Link to Google.com" />
Demo: