Well my first reaction is the same as yours, but since python is OSS the possibility does indeed exist that this could be emulated amongst other browsers withou

Well my first reaction is the same as yours, but since python is OSS the possibility does indeed exist that this could be emulated amongst other browsers without needing Silverlight. The runtime API they present to python though, while it seems to be just the DOM exposed, would still need to be documented and standardized.