How to handle invalid date entered

Hello,
I'd like to catch when a user has entered an invalid date and ideally notify them.
Assuming I have to detect this myself, my problem come when there doesn't seem to be an approriate event to trap. There's an OnChange JQEvent event but it appears to be triggered infrquently.
Do you have any recommendations.
Thanks in advance.
PS when attached to a datasource it appears that an invalid date is simply cleared (without any warning) which is proving to be quite confusing to end users whom say "I know I entered a date and it just disappear" (albeit in the wrong format)
I'd like to catch when a user has entered an invalid date and ideally notify them.
Assuming I have to detect this myself, my problem come when there doesn't seem to be an approriate event to trap. There's an OnChange JQEvent event but it appears to be triggered infrquently.
Do you have any recommendations.
Thanks in advance.
PS when attached to a datasource it appears that an invalid date is simply cleared (without any warning) which is proving to be quite confusing to end users whom say "I know I entered a date and it just disappear" (albeit in the wrong format)
