I just had a radical idea. I don't think River4 could run in the browser without some support routines from the server. But I don't actually think it needs that many. Just basic read and write functionality. All the parsing of XML and JSON are built-in to the browser. If it were possible, we'd be able to tap into a lot of unused CPU power and it would be incredibly easy to install, just load a web page, and you're up and running.