Generating an alphanumeric inquiry reference in

Currently evaluating/learning Mendix. Developing an inquiry logging forms based application. Wanted to generate an inquiry code from autonumber item prefixed by a abbreviated three letter descriptor. So, CMP678 would be a reference code for a compliment, COM679 would be a reference code for a complaint. Struggling to have the JavaScript widget generate these reference codes programatically and didn't want to delve into a Java Nanoscript routine. Not sue of best approach, please advise in general terms. Hope this description makes sense. Thanks in advance.
1 answers

Combine 2 fields.

Field 1 is the autonumber. Field 2 is the prefix (maybe an enumeration) and the third field is set with the combination of fields 1 and 2, this can be done via a microflow or nanoflow, no need for javascript for this.