kybernetikos shared with me a link to his Lispy language implementation on Javascript:
Javathcript allows you to script your web pages in a simple lisp variant. Once you include Javathcript.js, any script tags in your document with type=”text/lisp” will be evaluated. It will also download lisp files (only from the original server), if you have a script tag that has a src attribute. Finally, you can also evaluate lisp code from javascript using Javathcript.eval(lispString).
While it is not an exact implementation of any pre-existing variant of lisp, if you know lisp most of it should be familiar. If you don’t you might find it useful to follow a tutorial, e.g. this one. There will be differences between this implementation and others, but there is also much that is common.
It has more features than are shared in the blurb.
Looks pretty neat; check it out!