Gist from mistakes.io

index.js

// Hi!

(function() { return 'hi'; })();

// This is a sketchpad for Javascript
// ----------------------------------
// * 2 spaces are default so that stuff fits
//   on projectors.
// * some things might be weird, don't be afraid
// * console.whatever doesn't do anything
// * stuff on the right goes
//   through JSON.stringify
// * Hit Cmd-S to save as a Gist
// * it can load gists: for instance, this text is
//   https://gist.github.com/4679533 and is being
//   loaded because your page has #4679533
//   at the end. Do the same - create a new gist
//   and use its id at the end!
// * you can require() javascript files - check out
//   http://macwright.org/mistakes/#5051892

// help out with code or bug reports!
// https://github.com/tmcw/mistakes

// Let's get down to brass tacks:
// type a thing on the left, and the value
// of it will be displayed on the right:
42;