Usage:
qr.php?d=[data]&e=[(L,M,Q,H)]&s=[int]&v=[(1-40)]&t=[(J,G)]&size=[int]&download=[filename]

 d   = data         URL encoded data.
 e   = ECC level    L or M or Q or H   (default M)
 s   = module size  (dafault PNG:4 JPEG:8)
 v   = version      1-40 or Auto select if you do not set.
 t   = image type   J: jpeg image, G: GIF image, default: PNG image
 size = image size  Integer. Specifies the width & height of the image. Default 400. Max 1480.
 download = File name   URL encoded filename. If set, the content disposition will change to tell the browser to download the file.

For example:
php/qr.php?d=hello

Will encode a QR code containin the word "hello" with medium error correction, as a PNG, 400px wide & high.


qr.php?d=hello&e=Q&t=J&size=500&download=test

Will encode a QR code containin the word "hello" with Quartile error correction, as a JPG, 500px wide & high, and prompt you to download it as a file called "test.jpg".

Find out more at the QR Generator's GitHub.