Comparing Dates in Zoho Deluge

Comparing Dates in Zoho Deluge

It would be nice, that if I send them an invoice, that is due on a specific day, then I only give them the warning message of the invoice overdue, when the due date has passed:
something like this:
if (deadline > today) {

It would be nice, to know exactly how to compare the date formats in that case.

Thanks