It looks like your operating system is Windows. The windows driver model conflicts with WebUSB and might prevent this page from working with a printer.
To make this demo work you'll need to set up your driver correctly. You'll see errors in the developer console if it isn't configured correctly.
It looks like your operating system is Linux. The linux default driver conflicts with WebUSB and might prevent this page from working with a printer.
If a printer doesn't connect successfully you'll need to set up udev rules to load a different driver. You'll see errors in the developer console if it isn't configured correctly.
You may be able to find the correct USB IDs for your device by visiting either opening
chrome://usb-internalsin a new tab and clicking on the 'Devices' tab, or visiting the the USB ID Repository.
This demo uses WebUSB to function and your browser doesn't seem to have that available.
It looks like this URL is not using HTTPS, and WebUSB only works in a secure context. You'll need to load this page over HTTPS instead.
If you see this for a long time check the dev console for errors and try the
Connect a printer to your computer, then click Add Printer!
Once a printer is connected select it by clicking on it on the left.