Byzantine fault tolerant (BFT) applications are usually implemented with dedicated clients that interact with a set of replicas with some BFT protocol. In this paper, we explore the possibility of using web-based clients for interaction with a BFT service. Our contributions address the trustworthy deployment of client code and configuration in a browser-based execution environment (client bootstrapping), the design and implementation of a BFT client within the constraints of a browser-based JavaScript execution environment, and publish-subscribe extensions to the standard request/reply interaction model of BFT state machine model to simplify the implementation of efficient interactive web applications.