When users press the scan button in the web page a scanner appear and read a barcode, redirected to the web service you have defined and voila, you can provide any information on the product scanned: price, availability, quantity on hand, description, properties, promotions, etc.. It's up to you what information to provide.
Scan button opens the scanner and when the barcode is read, automatically calls a javascript code, from this javascript you can load an action, for example in php to connect a database.
You can create a page to update the inventory, search the stock of a book in your book store, a piece of clothing in your store and so on.
The home page is an example from the eidovirtual server, config the application to work on your own server and database.
Go button is optional and call the same javascript code manually.
2d codes may include special characters, the app can be configured to send data in hexadecimal.
Barcodeweb connects to your own web service.