Setting up a fillable pdf - scan item barcode, get it in one field and automate text in another

Hi everyone!

I have 2 fields in my form. first field is called barcode and i shoot with my scanner and get numbers on my field. I want to get field 2 autofilled with the corresponding text to the barcodenumber i get. 

How do i do that? Fairly new to JS so if anyone could write down the full codes for both fields I would appreciate it very much!

Thanks for an awesome forum!