I've created a custom module named Accounts to Contacts and it has the following fields:
Account to Contact 

Account

Contact

I want the value of Account to Contact = concatenated value of Account field + " > " + Contact field. I want the value to be automatically set when either Account or Contact is set. Since Account to Contact is a system field, it can't be empty. Account to Contact must be set client side _before_ any attempt is made to save the record, so I can't use a workflow. Is there any way to do this?