How check an inputField value ?

<b><i>Hi experts</i></b>,

How do you do when you want to check a value in a inputfield with type="date" ? My problem is that the field date is obligatory. When the inputfield is post with the form, this one is not null and not empty but equal to "0000-00-00" which correspond to "Sun Nov 30 00:00:00 CET 0002" in a Date type ! So how can I verify that my date field had not been set ?

<b><i>Best regards</i></b>.