The idea here is to have a 'use shipping/billing address' type of button that copies the user information from one block of fields to another identical set of fields.
this.field1.value = this.field2.value;
For posterity, this is the solution to the problem:
getField("field2").value = getField("field1").valueAsString;
Also, note that
field2 is set to
field1 so the order is backwards.