1. A system comprising a server computer in communication with a plurality of web clients running on one or more remote terminal devices, the server computer being configured to: receive a message from a first web client of the plurality of web clients, the message indicating that the first client currently has focus, wherein the message is transmitted by the first client with a cookie; determine whether each of the other web clients is receiving low-latency updates and is using the same cookie received from the first web client; in response to determining that one or more other web clients is using the same cookie and is receiving data using a low-latency update mechanism, downgrading the one or more other web clients to a high-latency update mechanism that provides updates less frequently than the low-latency update mechanism; and transmit updates to the first web client using the low-latency update mechanism.