Is it possible to embed a barcode reader into a website?

I don't think your monitor emits light at a high enough frequency or intensity for this to work, and you would need a device to read the barcode.

Cycloptichorn

A couple of issues back Esquire magazine had what they called an "augmented reality" issue.

Throughout the issue there would be odd looking boxes with a pattern of black and white squares inside. After downloading softwear from the magazine site you could hold the boxes up to your webcam and "make the issue come to life".

Alas, I don't have a webcam so I didn't get to try it out.

Here's the Esquire page about it: http://www.esquire.com/the-side/augmented-reality

Be sure to watch the video.

It seems to me that such technology could be made to read a barcode.