Change one field based on another's pre-filled contents

I have a field pulling variables out of the URL and putting that variable in, working just great. Problem is I can’t pass that text on to the form submission target, I have to remap it to a code based on its contents. Only a few values, so its not complex. But I’m trying to either do something in the form itself or use php to take the value in field one, identify the case, and based on that set hidden field 2 to the desired code.

There are some examples here that are close, but I’m by no means a php guru. And chain select seems to require the user to pick value 1 then it will fill with values. So that’s not quite what I’m looking for unless I’m just misunderstanding it.

Help is appreciated.

What’s the target, or do you just mean the submitted entry? This is hard to see without seeing the form. I don’t see why not, especially if the variables are being input into your fields already.

Are you trying to do a database search/query?