Getting Value from Parent Entity

I have two entities:  Client (Parent) and Matter (Child to Client) ...... we're a law firm.

Anyway, When displaying a matter form, the field that is the lookup for the parent client displays only the client number.  That's fine, but I also want to display the client's name on the matter form as well (read only).

I've done some research.  Right now, it seems my answer is adding an OnChange event to the Client Number field and then using Javascript and the Xrm.Page.data.entity.getParent function to get the Client entity and then populate my Matter Form field with the Client entity's Client-Name attribute.

Is that the best option or is there a simpler/better way to accomplish this?

Thanks from a beginner,
Glen