Auto filling time when another field is typed in

I have an 8 page form that is fillable. To make things easier for others, when they type their name in one field I would like the next field to auto insert the time, possibly the date as well. The field they type their name is "signature" and the next field is "time". I would like this to be visible and not change when the form is reopened. I am using Adobe Acrobat Pro Extended. After much googling I am not able to find a solution to make it work. I can format excel but adobe is stumping me. Thanks for any help.