Date/Time Field Restriction Record Producer

Hi All,

I have a date/time field on a record producer asking when the incident first occurred.

I have seen that the only way yo restrict this so people cannot add a date in the future is to have a script which validates this between the current date and the date selected when the field changes and then have a pop up message to warn the user.

I'm just not sure on how to script this?

Any help is greatly appreciated.

Thanks