ClojureScript is the Clojure language compiler that targets JavaScript. It compiles to Google Closure (not Clojure) JavaScript, but it can also target NodeJS. ClojureScript lets you use Clojure in the browser, adds Clojure data types to the JavaScript language, and allows for JavaScript to interact with the Clojure datatypes. Here's the side by side comparison https://himera.herokuapp.com/synonym.html

One of the most obvious additions to JavaScript is the ability to partition your JavaScript with namespaces.