Squeak used to be able to run in the browser, yea. It’s the property of a plugin called npsqueak, which stands for Netscape Plugin Squeak, and can be found in the standard set of plugin folders that come prepared to compile a new VM. Bert built it in 1999 and I think it was used by Etoys to some extent. I haven’t seen it running for well over a decade. As Bert also built SqueakJS it seems reasonable to think this is no longer a project he either uses or supports. The readme in the npsqueak plugin folder says more. 

Chris