A web server sends a first coordinator to a first browser of a first mobile device. The first coordinator is a set of instructions executable by the first browser. The web server also sends a second coordinator to a second browser of a second mobile device. The second coordinator is a set of instructions executable by the second browser. The first coordinator, when executed by the first browser, cause the first browser to: send a first request for information to the second browser, over the web server; wait until the requested information is received from the second coordinator over the web server; and when the requested information is received from the second coordinator, perform a first action based on the requested information received from the second coordinator. The first request includes a first token, and the requested information includes a next token.