StartEndDate Plugin

Ensures a start date field is on or before an end date field. Automatically cross-revalidates both fields when either changes.

Options

Option	Type	Description
format	string	Date format string. Supported tokens: YYYY, MM, DD. Separator: - or /.
startDate.field	string	Name of the start date field
startDate.message	string	Error message shown on the start field when start > end
endDate.field	string	Name of the end date field
endDate.message	string	Error message shown on the end field when end < start

Supported formats

Format	Example
YYYY-MM-DD	2025-12-31
DD/MM/YYYY	31/12/2025
MM/DD/YYYY	12/31/2025
YYYY/MM/DD	2025/12/31

Playground

Notes

• Cross-revalidation is automatic: when either field changes and validates, the other is revalidated immediately.
• If either field is empty, the constraint is not applied (defers to notEmpty or date validators).
• Invalid calendar dates (e.g. February 30) are treated as unparseable — the cross-field constraint is skipped.
• Equal dates are valid (inclusive comparison: start ≤ end).
• Multiple StartEndDate instances on the same form are supported (each instance has a unique internal key).