Why Selenium Server acts as Proxy for Selenium RC?

The motivation here is to conform to JavaScript's same-domain rule i.e., Same Origin Policy for JavaScript. We want the browser to be able to talk to both the web site being tested, and also to the selenium server itself. This presents a problem, since they will not normally be from the same domain. The solution is to have all communication go through the selenium server running as a proxy, where communication from the browser-side selenium test management harness is intercepted and swallowed up by the selenium server, and other queries are forwarded out to the web site being tested.