@islandgirl23
Yes it can be done.
suppose you have
1) dropdown field -> name of the field is phoneType
2) Text filed -> name of the field mobileType
open rule editor of the dropdown field and select the value commit and write below js:
if(this.value =="cellPhone"){
mobileType.value="smartphone";
or
guideBridge.resolveNode(mobileType).value="smartPhone";
}
Thanks,
Siva