From HeroRPG Manual
The Mail system allows players to send messages to one another. Each account has its own mailbox that is accessible from any character on that account. The mailbox allows players to view messages sent to them and messages they have sent to other players, as well as to compose new messages to other players.
The Mail system is completely coded in AJAX and thus only a single page load is necessary to view all of your mail and to send new messages.
