This is a Zoho CRM Client Script written in JS (using ZDK) that auto-populates the Phone field with a country dial code based on a picklist selection (e.g., "Dialing_Code").

This connection to Zoho CRM from Zoho CRM (sooooo meta, right?) is part of the prebuilt Zoho OAuth connection. Zoho has provided a number of out-of-the-box connections to Shopify, Survey Monkey, ...