>I'm showing the 4 digit year, but since the value is blank, the field is blank and then the user is enter a two-digit year and the default behavior is kicking in, but they don't see that until they try to save. So I'm trying to find a way to force the user to enter a 4 digit year.

They should see the year as soon as they leave the field. I've tried this and it works so for me. What is it that you're seeing?