Error while validating field values..

Hello Team,

I am seeking assistance with an issue in our Zoho CRM Quotes module. We have configured the following fields:

Quote Date: The date when the quote is created.
Quote Valid Through: A dropdown field with options like 30 days, 45 days, 60 days, 70 days, 90 days, etc.
Valid Until: A field that should display the calculated end date based on the "Quote Date" and the selected "Quote Valid Through" option.
Our client script calculates the "Valid Until" date based on the selection in "Quote Valid Through." However, we recently encountered an issue when the country's time zone settings were changed. This change also altered the date format, which caused our script to fail and display incorrect data (e.g., "NaNaNaN") in the "Valid Until" field.

To address this, I created a function to apply the current date format and integrated it into the client script. While this solution temporarily resolves the issue, we are concerned about the impact of future date format changes on the script’s functionality.

Could anyone please advise if there is a more robust solution or best practice to ensure that the script continues to work correctly despite changes in date formats or time zone settings? I would like to implement a solution that will maintain accuracy and functionality regardless of such changes.
I look forward to your guidance on how to resolve this issue effectively.

Thanks in Advance.

Thisai Moorthy.