Javascript virus?

As i accidently ran a javascript what was encrypted... I heard that javascript can have full access to your computer?.. I'm pretty freaked out atm.. I don't know how to react. Can it be a virus?

Javascript does NOT have any kind of computer access, as it's only a client-side scripting to create small animations, effects and some functionality on web pages. It doesn't has any knowledge of the underlying system, no access to file system, computer, network or any resource, and very limited knowledge about the browser you're running.
Viruses are never written in it, and while a few scripts may result in some info leaking in some insecure pages, the computer itself is out of its reach.