If you're starting out, I would recommend Clojure first. ClojureScript is basically the same language, although there are large pieces missing (since JS is single-threaded the only managed reference supported is atom, there is less support for runtime reflection like docstrings and exploring namespaces dynamically) but right now things are a bit rough around the edges, although they are getting better rapidly (see: ClojureScript One). It's just that when you get stuck with some issue with ClojureScript (like a browser connected REPL barfing on you or debugging the JS that comes out of the ClojureScript/Google Closure compiler, or understanding how macros work) I think it really helps to have a solid grasp of Clojure. See this for more details, although it might not mean much to someone new to Clojure: https://github.com/clojure/clojurescript/wiki/Differences-fr...

That being said, if you have some desire to experiment with alternatives to JS in the environments that is has traditionally been the only choice, ClojureScript is a compelling alternative, and ClojureScript One is an absolutely fantastic place to start. I have really enjoyed working with it and with ClojureScript in general, and huge props are deserved to those making it a better experience, because it's come a long way very fast.