Pass it a string parameter and it will determine whether it's a valid date or not based on this format "dd/MM/yyyy". However, if you're looking for a way to validate user date input, you should be aware that the Date object is very persistent about making what might appear to be invalid construction arguments into valid ones.
The following unit test code illustrates the point: Thank you for your interest in this question.
You can still see the absolute date/time by hovering over the field.
The date/time format reverts to absolute after a week.
Zeddnet is niet voor een speciale doelgroep bedacht.
Iederéén heeft een ‘minpuntje’ en dus is Zeddnet er voor iedereen.
(More info re specifying date formats is found at Date) In the above example, you wouldn't see the alert message since '01/03/2012' is a calendar-valid date in the specified format.