Autopopulate a date field

Hello,
I’m fairly new to Javascript coding but I’m using it for one of the PHP pages I’m putting together.

It’s basically a form in which 3 different people need to sign off on before completion.

I’d like when all 3 of the names are input into the form, for a 4th text field to autopopulate the current date.

Any help would be greatly appreciated.

Also in #JavaScript _↴