Problem with date format mysql - classic asp

Hi all,

I'm having an issue with updating a date field in classic asp.
Data is stored in mysql.
Issue: Users are given the option to update the projectdeadline - However if they choose not to, the current value should stay in the database.

When the user gets to the form, the date is (if one has been entered) displayed dd-mm-yyyy. If the user actively chooses a new date the data displayed in the form field changes to the form field required by mysql (yyyy-mm-dd). But if they do nothing and just leave it there, the date is still displayed dd-mm-yyyy and thus does not get accepted as a valid date by the mysql database. Any ideas?

BR
Michael