How do I setup Data Validation on Record Edits?

Hello,

I am trying to prevent listing errors by creating a Data Validation Script that would prevent employees from updating the "Classification" Field on Inventory Items (except for Parent SKUs) if the "Item Weight" and "Dimweight" Fields are empty.

Here is what I have tried so far:

Script File

/** * @NApiVersion 2.x * @NScriptType UserEventScript */define(['N/record', 'N/error', 'N/log'], function(record, error, log) {        function beforeSubmit(context) {        log.debug('Script Triggered', 'beforeSubmit function has been triggered.');        // Only proceed if this is an edit operation        if (context.type !== context.UserEventType.EDIT) {            log.debug('Exit Condition', 'The script is not running on an edit action, so it will exit.');