The canonical analytics architecture today consists of a browser connected to a backend in the cloud. In all deployments that we are aware of, the browser is simply a dumb rendering endpoint. As an alternative, this paper explores split-execution architectures that push analytics capabilities into the browser. We show that, by taking advantage of typed arrays and asm.js, it is possible to build an analytical RDBMS in JavaScript that runs in a browser, achieving performance rivaling native databases. To support interactive data exploration, our Afterburner prototype automatically generates local materialized views from a backend database that are then shipped to the browser to facilitate subsequent interactions seamlessly and efficiently. We compare this architecture to several alternative deployments, experimentally demonstrating performance parity, while at the same time providing additional advantages in terms of administrative and operational simplicity.