Validation and MaxValue

I am using a control that allows me to enter a number on a web form. Ex: We have a field for year. I can set a max value to 2020. What should happen if the user enters 9999?

Should it?:
1) Automatically change the value to 2020 when the control loses focus?
2) Allow 9999 in the display, but display an error message like (Max value allowed is 2020).
3) Other?

What do you think?

I like option 1, but I have a customer that wants the second option. Have have you dealt with this?

Open in new tab

OK, this is cool. I just had to share.
You can open a link in a tew tab in IE7 simply by holding down the Ctrl key when you click on the link.