The latest version 2.12.0 of the Bitcoin and Altcoin Wallets free WordPress plugin introduces the ability to refresh front-end data periodically.

Balances and past transactions are refreshed via polling the JSON API interface. The admin can choose the polling interval. If you expect to have many concurrent users, make sure not to set the polling interval to too low a value. The polling mechanism can potentially cause a high load on your server.

The frontend UIs do not poll your server if the page is in a background tab, or if the browser is minimized. This is done using the Visibility API.

Additionally, data is refreshed whenever the page becomes visible and after the user submits a new transaction.