Add Curent Date & Time to PDF when Printed

This is my first post so please excuse any ignorance.

Basically we are in the process of creating electronic copies of SOP’s and putting them on our file server for all staff to access. Due to regulations, when these SOP’s are printed they would need to have the current date and time in which the SOP was printed, ideally like a watermark faded diagonally across the page but even if it was something on the bottom or top this would also do the trick.

It should read "Only Valid on Date of Printing - <Current Date><Current Time>

Could somebody please tell me if something like this is possible by incorporating JavaScript into the PDF.

Any assistance I would be grateful.

Thanks.

Keith.