when name entered in one text field, add both name + current date to another

Can someone correct my script?

I have 4 people that I want to use a form, and when they type their names at the top of the form, it writes the same name and current date in a field at the bottom.

This is what I have, but it's not working:

if (event.value=="John Doe") {

    this.getField("Prepared by and date").value = "John Doe util.printd("mm/dd/yyyy", new Date())";

} // end switch;

if (event.value=="Jenny Doe") {

    this.getField("Prepared by and date").value = "Jenny Doe util.printd("mm/dd/yyyy", new Date())";

} // end switch;

if (event.value=="Joy Doe") {

    this.getField("Prepared by and date").value = "Joy Doe util.printd("mm/dd/yyyy", new Date())";

} // end switch;

if (event.value=="James Doe") {

    this.getField("Prepared by and date").value = "James Doe util.printd("mm/dd/yyyy", new Date())";

}

FYI I'm a novice. Thanks in Advance