Interactive interpreter

SeriousJS (ctrl+enter or cmd+enter to run) Javascript

Remember that SeriousJS is designed for module compilation, so you'll see some oddities if you're used to CoffeeScript output. For instance, if at the global scope you write "a = 8", then in order to work with NodeJS as well as RequireJS, SeriousJS will put "this.a=a = 8" for you, as it needs to expose the variable at the module level as well as locally.