Christ, that's some serious bubble effect you've got there. Not only is it possible, it's quite common. Until about 2 years ago the only place javascript ran was in the browser or a handful of experimental projects. And big, traditionally-organized teams often have people who are responsible only for the browser side of things.
Perhaps in silicon valley, but outside it most of us were expected to be a jack of all trades. There may be a specialized DBA, and a designer, but we were responsible for understanding the full stack. The designer worked in photoshop, and the DBA only came in on designing the tables and optimizations, but we were responsible for the real work.
