Finding variables in the "Prompt for User Input" entered values

I'm in a midst of making a macro, which makes a instant template for my jobs. Currently, I'm stuck on making the "Prompt for User Input", to identified a entered value, for example, "21881_BigSalesFlyers" into two different variables. The job number (21881) & name (BigSalesFlyers). Is it's possible?

There are various routes – one approach is to use JSON tokens with [1], [2] subscripts:

Split phrase.kmmacros (20.0 KB)

Code snippet creating JSON from JS action:

(() => {
    'use strict';

        kme = Application('Keyboard Maestro Engine'),
        kmVar = k => kme.getvariable(k);

    return JSON.stringify(