Barcode Scanning

I think you just give the desired input field focus and scan the label code.

Thanks for the reply Salus1 , unfortunately I have not even got to that point yet. I am more looking for

1. Where to put the code . I assume it's Javascript onload for the input field.
   
2. Since it's done wirelessly , How would the scanner know the input field. ( this is where I am confused a bit )
   
3. Since it only needs to input the UPC code , then the next field would be a carriage return and the amount of inventory, I am not sure why I would need focus as it is already focused isn't it? or what I am asking is what would be an example code to focus it to pick up the wireless scanner or how does the wireless scanner know to input to that particular field on the add page?
   Thanks for any replies.

I think I'm missing something. Do you want to scan an image of a UPC code or scan the code, have scanner decode it and enter the decoded data into a text field?

I need the wireless scanner to scan the package UPC code and input the numbers not the image into an input field. If exists then I would use dependent dropdowns to auto fill the rest of the info .
Now if I use another solution like Quagga , then yes I would have to decode the image automatically and focus the input field with the UPC code number in a text field.

The scanner will decode the label for you and enter it as text into the active field.

There is no need to write any code. A Barcode scanner or a similar device will decode the barcode or QR code for you and will enter it into the current form field. In other words, those scanners basically act as a keyboard, you just need to configure them to send TAB or ENTER after the code, so focus moves to the next field.
I guess it would make sense to make the field that accepts the input from the scanner the first field on the form.